ARM: dts: am335x/437x/57xx: remove unneeded unit name for gpio-leds nodes

This patch fixes the following DTC warnings for many boards:

"Node /leds/led@1 has a unit name, but no reg property"

Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/boot/dts/am335x-nano.dts

@@ -27,7 +27,7 @@
 	leds {
 		compatible = "gpio-leds";
 
-		led@0 {
+		led0 {
 			label = "nanobone:green:usr1";
 			gpios = <&gpio1 5 0>;
 			default-state = "off";