ARM: dts: am335x/am437x: remove unneeded unit name for gpio-matrix-keypad

This patch fixes the following DTC warnings for many boards:

"Node /matrix_keypad@0 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

@@ -53,7 +53,7 @@ wlan_en_reg: fixedregulator@2 {
 		enable-active-high;
 	};
 
-	matrix_keypad: matrix_keypad@0 {
+	matrix_keypad: matrix_keypad0 {
 		compatible = "gpio-matrix-keypad";
 		debounce-delay-ms = <5>;
 		col-scan-delay-us = <2>;

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

@@ -58,7 +58,7 @@ backlight {
 		default-brightness-level = <8>;
 	};
 
-	matrix_keypad: matrix_keypad@0 {
+	matrix_keypad: matrix_keypad0 {
 		compatible = "gpio-matrix-keypad";
 		debounce-delay-ms = <5>;
 		col-scan-delay-us = <2>;

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

@@ -64,7 +64,7 @@ sound_master: simple-audio-card,codec {
 		};
 	};
 
-	matrix_keypad: matrix_keypad@0 {
+	matrix_keypad: matrix_keypad0 {
 		compatible = "gpio-matrix-keypad";
 
 		pinctrl-names = "default";

arch/arm/boot/dts/am43x-epos-evm.dts

@@ -67,7 +67,7 @@ lcd_in: endpoint {
 		};
 	};
 
-	matrix_keypad: matrix_keypad@0 {
+	matrix_keypad: matrix_keypad0 {
 		compatible = "gpio-matrix-keypad";
 		debounce-delay-ms = <5>;
 		col-scan-delay-us = <2>;