ARM: shmobile: kzm9g-reference dts: Add labels for the LEDs

The LEDs on the kzm9g board are labeled using upper-case characters.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/boot/dts/sh73a0-kzm9g-reference.dts

@@ -101,15 +101,19 @@ leds {
 		compatible = "gpio-leds";
 		led1 {
 			gpios = <&pfc 20 GPIO_ACTIVE_LOW>;
+			label = "LED1";
 		};
 		led2 {
 			gpios = <&pfc 21 GPIO_ACTIVE_LOW>;
+			label = "LED2";
 		};
 		led3 {
 			gpios = <&pfc 22 GPIO_ACTIVE_LOW>;
+			label = "LED3";
 		};
 		led4 {
 			gpios = <&pfc 23 GPIO_ACTIVE_LOW>;
+			label = "LED4";
 		};
 	};