arm64: dts: imx8mq-librem5: add RGB pwm notification leds

Describe the RGB notification leds on the Librem 5 phone.
Use the common defines so we're sure to adhere to the common patterns,
use predefined led colors and functions so we're being warned in case
of deprecations.
Signed-off-by: Guido Günther <agx@sigxcpu.org>
Signed-off-by: Martin Kepplinger <martin.kepplinger@puri.sm>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8mq-librem5.dtsi

@@ -7,6 +7,7 @@
 
 #include "dt-bindings/input/input.h"
 #include <dt-bindings/interrupt-controller/irq.h>
+#include <dt-bindings/leds/common.h>
 #include "dt-bindings/pwm/pwm.h"
 #include "dt-bindings/usb/pd.h"
 #include "imx8mq.dtsi"
@@ -54,6 +55,31 @@ key-vol-up {
 		};
 	};
 
+	led-controller {
+		compatible = "pwm-leds";
+
+		led-0 {
+			function = LED_FUNCTION_STATUS;
+			color = <LED_COLOR_ID_BLUE>;
+			max-brightness = <248>;
+			pwms = <&pwm2 0 50000 0>;
+		};
+
+		led-1 {
+			function = LED_FUNCTION_STATUS;
+			color = <LED_COLOR_ID_GREEN>;
+			max-brightness = <248>;
+			pwms = <&pwm4 0 50000 0>;
+		};
+
+		led-2 {
+			function = LED_FUNCTION_STATUS;
+			color = <LED_COLOR_ID_RED>;
+			max-brightness = <248>;
+			pwms = <&pwm3 0 50000 0>;
+		};
+	};
+
 	reg_aud_1v8: regulator-audio-1v8 {
 		compatible = "regulator-fixed";
 		pinctrl-names = "default";