ARM: at91/dt: replace gpio-key,wakeup with wakeup-source property

Though the keyboard driver for GPIO buttons(gpio-keys) will continue to
check for/support the legacy "gpio-key,wakeup" boolean property to
enable gpio buttons as wakeup source, "wakeup-source" is the new
standard binding.

This patch replaces the legacy "gpio-key,wakeup" with the unified
"wakeup-source" property in order to avoid any futher copy-paste
duplication.

Cc: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
diff --git a/arch/arm/boot/dts/animeo_ip.dts b/arch/arm/boot/dts/animeo_ip.dts
index 4e0ad3b..0962f2f 100644
--- a/arch/arm/boot/dts/animeo_ip.dts
+++ b/arch/arm/boot/dts/animeo_ip.dts
@@ -155,21 +155,21 @@
 			label = "keyswitch_in";
 			gpios = <&pioB 1 GPIO_ACTIVE_HIGH>;
 			linux,code = <28>;
-			gpio-key,wakeup;
+			wakeup-source;
 		};
 
 		error_in {
 			label = "error_in";
 			gpios = <&pioB 2 GPIO_ACTIVE_HIGH>;
 			linux,code = <29>;
-			gpio-key,wakeup;
+			wakeup-source;
 		};
 
 		btn {
 			label = "btn";
 			gpios = <&pioC 23 GPIO_ACTIVE_HIGH>;
 			linux,code = <31>;
-			gpio-key,wakeup;
+			wakeup-source;
 		};
 	};
 };