ARM: shmobile: koelsch dts: Add labels for the LEDs

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

arch/arm/boot/dts/r8a7791-koelsch.dts

@@ -149,12 +149,15 @@
 		compatible = "gpio-leds";
 		led6 {
 			gpios = <&gpio2 19 GPIO_ACTIVE_HIGH>;
+			label = "LED6";
 		};
 		led7 {
 			gpios = <&gpio2 20 GPIO_ACTIVE_HIGH>;
+			label = "LED7";
 		};
 		led8 {
 			gpios = <&gpio2 21 GPIO_ACTIVE_HIGH>;
+			label = "LED8";
 		};
 	};