Missing license references in DTS files

[kestewart]

Describe the bug
Missing SPDX license reference in the source file:

To Reproduce
See headers in the following files:

zephyr-master/dts/arm/armv6-m.dtsi
zephyr-master/dts/arm/armv7-m.dtsi
zephyr-master/dts/arm/armv8-m.dtsi
zephyr-master/dts/arm/nordic/nrf51822.dtsi
zephyr-master/dts/arm/nordic/nrf52810.dtsi
zephyr-master/dts/arm/nordic/nrf52832.dtsi
zephyr-master/dts/arm/nordic/nrf52840.dtsi
zephyr-master/dts/arm/nordic/nrf5_common.dtsi
zephyr-master/dts/arm/nxp/nxp_k6x.dtsi
zephyr-master/dts/arm/nxp/nxp_kl25z.dtsi
zephyr-master/dts/arm/nxp/nxp_kw2xd.dtsi
zephyr-master/dts/arm/nxp/nxp_kw40z.dtsi
zephyr-master/dts/arm/nxp/nxp_kw41z.dtsi
zephyr-master/dts/arm/silabs/efm32hg.dtsi
zephyr-master/dts/arm/silabs/efm32wg.dtsi
zephyr-master/dts/arm/silabs/efr32fg1p.dtsi
zephyr-master/dts/arm/silabs/efr32mg.dtsi
zephyr-master/dts/arm/ti/cc32xx.dtsi
zephyr-master/dts/arm/ti/lm3s6965.dtsi
zephyr-master/dts/arm/ti/msp432p4xx.dtsi

zephyr-master/dts/bindings/device_node.yaml.template

zephyr-master/dts/bindings/arm/atmel,sam0-sercom.yaml
zephyr-master/dts/bindings/arm/nordic,nrf-ficr.yaml
zephyr-master/dts/bindings/arm/nordic,nrf-spu.yaml
zephyr-master/dts/bindings/can/can.yaml
zephyr-master/dts/bindings/can/st,stm32-can.yaml
zephyr-master/dts/bindings/clock/st,stm32-rcc.yaml
zephyr-master/dts/bindings/flash_controller/atmel,sam0-nvmctrl.yaml
zephyr-master/dts/bindings/flash_controller/flash-controller.yaml
zephyr-master/dts/bindings/flash_controller/nordic,nrf51-flash-controller.yaml
zephyr-master/dts/bindings/flash_controller/nordic,nrf52-flash-controller.yaml
zephyr-master/dts/bindings/flash_controller/nordic,nrf91-flash-controller.yaml
zephyr-master/dts/bindings/flash_controller/nxp,kinetis-ftfa.yaml
zephyr-master/dts/bindings/flash_controller/nxp,kinetis-ftfe.yaml
zephyr-master/dts/bindings/flash_controller/nxp,kinetis-ftfl.yaml
zephyr-master/dts/bindings/flash_controller/st,stm32f0-flash-controller.yaml
zephyr-master/dts/bindings/flash_controller/st,stm32f2-flash-controller.yaml
zephyr-master/dts/bindings/flash_controller/st,stm32f3-flash-controller.yaml
zephyr-master/dts/bindings/flash_controller/st,stm32f4-flash-controller.yaml
zephyr-master/dts/bindings/flash_controller/st,stm32f7-flash-controller.yaml
zephyr-master/dts/bindings/flash_controller/st,stm32l4-flash-controller.yaml
zephyr-master/dts/bindings/gpio/arm,cmsdk-gpio.yaml
zephyr-master/dts/bindings/gpio/atmel,sam-gpio.yaml
zephyr-master/dts/bindings/gpio/atmel,sam0-gpio.yaml
zephyr-master/dts/bindings/gpio/nxp,kinetis-gpio.yaml
zephyr-master/dts/bindings/gpio/openisa,rv32m1-gpio.yaml
zephyr-master/dts/bindings/gpio/silabs,efm32-gpio-port.yaml
zephyr-master/dts/bindings/gpio/silabs,efm32-gpio.yaml
zephyr-master/dts/bindings/gpio/silabs,efr32mg12-gpio-port.yaml
zephyr-master/dts/bindings/gpio/silabs,efr32mg12-gpio.yaml
zephyr-master/dts/bindings/gpio/silabs,efr32xg1-gpio-port.yaml
zephyr-master/dts/bindings/gpio/silabs,efr32xg1-gpio.yaml
zephyr-master/dts/bindings/i2c/ti,cc32xx-i2c.yaml
zephyr-master/dts/bindings/iio/adc/atmel,sam-afec.yaml
zephyr-master/dts/bindings/interrupt-controller/arm,v6m-nvic.yaml
zephyr-master/dts/bindings/interrupt-controller/arm,v7m-nvic.yaml
zephyr-master/dts/bindings/interrupt-controller/arm,v8m-nvic.yaml
zephyr-master/dts/bindings/interrupt-controller/intel,cavs-intc.yaml
zephyr-master/dts/bindings/interrupt-controller/intel,ioapic.yaml
zephyr-master/dts/bindings/interrupt-controller/intel,mvic.yaml
zephyr-master/dts/bindings/interrupt-controller/shared-irq.yaml
zephyr-master/dts/bindings/interrupt-controller/snps,designware-intc.yaml
zephyr-master/dts/bindings/interrupt-controller/xtensa,intc.yaml
zephyr-master/dts/bindings/led/nxp,pca9633.yaml
zephyr-master/dts/bindings/led/ti,lp3943.yaml
zephyr-master/dts/bindings/led/ti,lp5562.yaml
zephyr-master/dts/bindings/led_strip/apa,apa-102.yaml
zephyr-master/dts/bindings/mtd/partition.yaml
zephyr-master/dts/bindings/mtd/soc-nv-flash.yaml
zephyr-master/dts/bindings/pinctrl/atmel,sam0-pinmux.yaml
zephyr-master/dts/bindings/pinctrl/nxp,kinetis-pinmux.yaml
zephyr-master/dts/bindings/pinctrl/openisa,rv32m1-pinmux.yaml
zephyr-master/dts/bindings/pinctrl/st,stm32-pinmux.yaml
zephyr-master/dts/bindings/pwm/nordic,nrf-pwm.yaml
zephyr-master/dts/bindings/pwm/nordic,nrf-sw-pwm.yaml
zephyr-master/dts/bindings/pwm/st,stm32-pwm.yaml
zephyr-master/dts/bindings/serial/altera,jtag-uart.yaml
zephyr-master/dts/bindings/serial/arm,cmsdk-uart.yaml
zephyr-master/dts/bindings/serial/arm,pl011.yaml
zephyr-master/dts/bindings/serial/atmel,sam-uart.yaml
zephyr-master/dts/bindings/serial/atmel,sam-usart.yaml
zephyr-master/dts/bindings/serial/atmel,sam0-uart.yaml
zephyr-master/dts/bindings/serial/nordic,nrf-uart.yaml
zephyr-master/dts/bindings/serial/nordic,nrf-uarte.yaml
zephyr-master/dts/bindings/serial/ns16550.yaml
zephyr-master/dts/bindings/serial/nxp,kinetis-lpsci.yaml
zephyr-master/dts/bindings/serial/nxp,kinetis-lpuart.yaml
zephyr-master/dts/bindings/serial/nxp,kinetis-uart.yaml
zephyr-master/dts/bindings/serial/openisa,rv32m1-lpuart.yaml
zephyr-master/dts/bindings/serial/silabs,gecko-leuart.yaml
zephyr-master/dts/bindings/serial/silabs,gecko-usart.yaml
zephyr-master/dts/bindings/serial/st,stm32-lpuart.yaml
zephyr-master/dts/bindings/serial/st,stm32-uart.yaml
zephyr-master/dts/bindings/serial/st,stm32-usart.yaml
zephyr-master/dts/bindings/serial/ti,cc32xx-uart.yaml
zephyr-master/dts/bindings/serial/ti,msp432p4xx-uart.yaml
zephyr-master/dts/bindings/serial/ti,stellaris-uart.yaml
zephyr-master/dts/bindings/serial/uart.yaml
zephyr-master/dts/bindings/serial/xtensa,esp32-uart.yaml
zephyr-master/dts/bindings/timer/arm,cmsdk-dtimer.yaml
zephyr-master/dts/bindings/timer/arm,cmsdk-timer.yaml
zephyr-master/dts/bindings/timer/openisa,rv32m1-lptmr.yaml
zephyr-master/dts/bindings/timer/st,stm32-timers.yaml
zephyr-master/dts/bindings/usb/atmel,sam0-usb.yaml
zephyr-master/dts/bindings/watchdog/arm,cmsdk-watchdog.yaml
zephyr-master/dts/bindings/watchdog/atmel,sam0-watchdog.yaml

zephyr-master/dts/common/common.dts
zephyr-master/dts/common/skeleton.dtsi

zephyr-master/dts/nios2/nios2-qemu.dtsi
zephyr-master/dts/nios2/nios2f.dtsi

zephyr-master/dts/riscv32/riscv32-fe310.dtsi

zephyr-master/dts/xtensa/intel_s1000.dtsi

zephyr-master/dts/Kconfig

Expected behavior
Expect to see comment with
SPDX-License-Identifier: Apache-2.0
in each of the files, like the rest of the repository.

In cases where the file is not an Apache-2.0 one,
the appropriate SPDX Licence Identifier should be used.

Impact
Showstopper. Licensing needs to be clean and comprehensive before LTS is released, as this will impact all products trying to generate an accurate SBOM, as well as impact CII Gold badge status.

Environment (please complete the following information):
Version used: 1.14-rc3