ARM: dts: stm32: Update LED node for stm32mp15xx-dkx board

Add led-red node for stm32mp15xx-dkx, this LED is used as status
LED in U-Boot.
Update led-blue node by adding color property and replacing obsolete
label property by function property.

Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com>
Link: https://lore.kernel.org/r/20251113-upstream_update_led_nodes-v2-13-45090db9e2e5@foss.st.com
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>

Author: Patrice Chotard

arch/arm/boot/dts/st/stm32mp15xx-dkx.dtsi

@@ -5,6 +5,7 @@
  */
 
 #include <dt-bindings/gpio/gpio.h>
+#include <dt-bindings/leds/common.h>
 #include <dt-bindings/mfd/st,stpmic1.h>
 
 / {
@@ -64,11 +65,18 @@
 	led {
 		compatible = "gpio-leds";
 		led-blue {
-			label = "heartbeat";
+			function = LED_FUNCTION_HEARTBEAT;
+			color = <LED_COLOR_ID_BLUE>;
 			gpios = <&gpiod 11 GPIO_ACTIVE_HIGH>;
 			linux,default-trigger = "heartbeat";
 			default-state = "off";
 		};
+
+		led-red {
+			function = LED_FUNCTION_STATUS;
+			color = <LED_COLOR_ID_RED>;
+			gpios = <&gpioa 13 GPIO_ACTIVE_LOW>;
+		};
 	};
 
 	sound {