dts: mimxrt685_evk: Map all pins of Flexcomm #1

Map all pins of RT685's Flexcomm #1 peripheral.

Needed for opration of Flexcomm #1 in I2S mode or Flexcomm #3 in I2S
mode with shared signals.

Signed-off-by: Vit Stanicek <vit.stanicek@nxp.com>

Author: VitekST

boards/nxp/mimxrt685_evk/mimxrt685_evk-pinctrl.dtsi

@@ -26,7 +26,9 @@
 
 	pinmux_flexcomm1_i2s: pinmux_flexcomm1_i2s {
 		group0 {
-			pinmux = <FC1_RXD_SDA_MOSI_DATA_PIO0_9>;
+			pinmux = <FC1_RXD_SDA_MOSI_DATA_PIO0_9>,
+				 <FC1_TXD_SCL_MISO_WS_PIO0_8>,
+				 <FC1_SCK_PIO0_7>;
 			input-enable;
 			slew-rate = "normal";
 			drive-strength = "high";