ARM: dts: am335x/am437x: remove unneeded unit name for gpio-keys nodes

This patch fixes the following DTC warnings for many boards:

"Node /gpio_keys/button0@10 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-evm.dts

@@ -73,20 +73,20 @@ &gpio1 26 GPIO_ACTIVE_HIGH		/* Bank1, pin26 */
 				0x0201006c>;	/* DOWN */
 	};
 
-	gpio_keys: volume_keys@0 {
+	gpio_keys: volume_keys0 {
 		compatible = "gpio-keys";
 		#address-cells = <1>;
 		#size-cells = <0>;
 		autorepeat;
 
-		switch@9 {
+		switch9 {
 			label = "volume-up";
 			linux,code = <115>;
 			gpios = <&gpio0 2 GPIO_ACTIVE_LOW>;
 			wakeup-source;
 		};
 
-		switch@10 {
+		switch10 {
 			label = "volume-down";
 			linux,code = <114>;
 			gpios = <&gpio0 3 GPIO_ACTIVE_LOW>;

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

@@ -102,31 +102,31 @@ led@4 {
 		};
 	};
 
-	gpio_buttons: gpio_buttons@0 {
+	gpio_buttons: gpio_buttons0 {
 		compatible = "gpio-keys";
 		#address-cells = <1>;
 		#size-cells = <0>;
 
-		switch@1 {
+		switch1 {
 			label = "button0";
 			linux,code = <0x100>;
 			gpios = <&gpio2 3 GPIO_ACTIVE_HIGH>;
 		};
 
-		switch@2 {
+		switch2 {
 			label = "button1";
 			linux,code = <0x101>;
 			gpios = <&gpio2 2 GPIO_ACTIVE_HIGH>;
 		};
 
-		switch@3 {
+		switch3 {
 			label = "button2";
 			linux,code = <0x102>;
 			gpios = <&gpio0 30 GPIO_ACTIVE_HIGH>;
 			wakeup-source;
 		};
 
-		switch@4 {
+		switch4 {
 			label = "button3";
 			linux,code = <0x103>;
 			gpios = <&gpio2 5 GPIO_ACTIVE_HIGH>;

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

@@ -616,21 +616,21 @@ &buttons {
 	#address-cells = <1>;
 	#size-cells = <0>;
 
-	button@0 {
+	button0 {
 		label = "home";
 		linux,code = <KEY_HOME>;
 		gpios = <&gpio1 22 GPIO_ACTIVE_LOW>;
 		wakeup-source;
 	};
 
-	button@1 {
+	button1 {
 		label = "menu";
 		linux,code = <KEY_MENU>;
 		gpios = <&gpio1 23 GPIO_ACTIVE_LOW>;
 		wakeup-source;
 	};
 
-	buttons@2 {
+	buttons2 {
 		label = "power";
 		linux,code = <KEY_POWER>;
 		gpios = <&gpio0 7 GPIO_ACTIVE_LOW>;

arch/arm/boot/dts/am437x-idk-evm.dts

@@ -104,7 +104,7 @@ gpio_keys: gpio_keys {
 		#address-cells = <1>;
 		#size-cells = <0>;
 
-		switch@0 {
+		switch0 {
 			label = "power-button";
 			linux,code = <KEY_POWER>;
 			gpios = <&gpio4 2 GPIO_ACTIVE_LOW>;