ARM: dts: keystone: align LED node names with dtschema

The node names should be generic and DT schema expects certain pattern:

keystone-k2hk-evm.dtb: leds: 'debug1_1', 'debug1_2', 'debug2', 'debug3' do not match any of the regexes: '(^led-[0-9a-f]$|led)', 'pinctrl-[0-9]+'

Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Krzysztof Kozlowski <[e-mail]>

arch/arm/boot/dts/keystone-k2hk-evm.dts

···
 
 	leds {
 		compatible = "gpio-leds";
-		debug1_1 {
+		led-debug-1-1 {
 			label = "keystone:green:debug1";
 			gpios = <&gpio0 12 GPIO_ACTIVE_HIGH>; /* 12 */
 		};
 
-		debug1_2 {
+		led-debug-1-2 {
 			label = "keystone:red:debug1";
 			gpios = <&gpio0 13 GPIO_ACTIVE_HIGH>; /* 13 */
 		};
 
-		debug2 {
+		led-debug-2 {
 			label = "keystone:blue:debug2";
 			gpios = <&gpio0 14 GPIO_ACTIVE_HIGH>; /* 14 */
 		};
 
-		debug3 {
+		led-debug-3 {
 			label = "keystone:blue:debug3";
 			gpios = <&gpio0 15 GPIO_ACTIVE_HIGH>; /* 15 */
 		};