arm64: dts: imx8mq-librem5: use multicolor leds description for RGB led

As Documentation/leds/well-known-leds.txt says, "Phones usually have
multi-color status LED." Fix that for the Librem 5 mobile phone board.
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

@@ -56,27 +56,27 @@ key-vol-up {
 	};
 
 	led-controller {
-		compatible = "pwm-leds";
+		compatible = "pwm-leds-multicolor";
 
-		led-0 {
+		multi-led {
+			color = <LED_COLOR_ID_RGB>;
 			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-0 {
+				color = <LED_COLOR_ID_BLUE>;
+				pwms = <&pwm2 0 50000 0>;
+			};
 
-		led-2 {
-			function = LED_FUNCTION_STATUS;
-			color = <LED_COLOR_ID_RED>;
-			max-brightness = <248>;
-			pwms = <&pwm3 0 50000 0>;
+			led-1 {
+				color = <LED_COLOR_ID_GREEN>;
+				pwms = <&pwm4 0 50000 0>;
+			};
+
+			led-2 {
+				color = <LED_COLOR_ID_RED>;
+				pwms = <&pwm3 0 50000 0>;
+			};
 		};
 	};