ARM: dts: mx6: Disable the keypad in the dtsi files

When booting a board that does not have a keypad (such as imx6q-sabresd) the
following error is seen on boot:

imx-keypad 20b8000.kpp: OF: linux,keymap property not defined in /soc/aips-bus@02000000/kpp@020b8000
imx-keypad 20b8000.kpp: failed to build keymap
imx-keypad: probe of 20b8000.kpp failed with error -2

Let's disable the keypad functionality in the dtsi files and let each board dts
enable it when needed.
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Shawn Guo <shawn.guo@freescale.com>

arch/arm/boot/dts/imx6qdl-tx6.dtsi

@@ -620,6 +620,7 @@ MATRIX_KEY(2, 6, KEY_KP7) /* 0x02060047 */
 		MATRIX_KEY(2, 7, KEY_KP8) /* 0x02070048 */
 		MATRIX_KEY(2, 2, KEY_KP9) /* 0x02020049 */
 	>;
+	status = "okay";
 };
 
 &pwm1 {

arch/arm/boot/dts/imx6qdl.dtsi

@@ -485,6 +485,7 @@ kpp: kpp@020b8000 {
 				reg = <0x020b8000 0x4000>;
 				interrupts = <0 82 IRQ_TYPE_LEVEL_HIGH>;
 				clocks = <&clks IMX6QDL_CLK_IPG>;
+				status = "disabled";
 			};
 
 			wdog1: wdog@020bc000 {

arch/arm/boot/dts/imx6sl.dtsi

@@ -403,6 +403,7 @@ kpp: kpp@020b8000 {
 				reg = <0x020b8000 0x4000>;
 				interrupts = <0 82 IRQ_TYPE_LEVEL_HIGH>;
 				clocks = <&clks IMX6SL_CLK_DUMMY>;
+				status = "disabled";
 			};
 
 			wdog1: wdog@020bc000 {