nrf52840.dtsi contains "0x" in device label

[barsok]

USBD has description:

usbd: usbd@0x40027000 {

which causes a warning during compilation of the devicetree

-- Generating zephyr/include/generated/generated_dts_board.h
nrf52840_pca10056.dts_compiled: Warning (unit_address_format): Node /soc/usbd@0x40027000 unit name should not have leading "0x"
extract_dts_includes.py: Merge of 'title': 'Nordic nRF52 USBD' overwrites 'USB Base Structure'.
extract_dts_includes.py: Merge of 'node_type': '['USB-EP', 'USB']' overwrites '['USB']'.
extract_dts_includes.py: Merge of 'description': 'This binding gives a base representation of the Nordic >nRF52 USB device controller

and strangely looking labels in generated_dts_board.h:

#define NORDIC_NRF_USBD_0X40027000_BASE_ADDRESS 0x40027000

[barsok]

BTW the fixup file for nrf52840 also needs to be amended as it contains defines with the 0x

[alext-mkrs]

I take this one if no one objects.