ARM: DT: Kirkwood: Use symbolic names from input.h

Replace the numeric key value with a symbolic name from
<bt-bindings/input/input.h>

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
diff --git a/arch/arm/boot/dts/kirkwood-ns2-common.dtsi b/arch/arm/boot/dts/kirkwood-ns2-common.dtsi
index 2fcb82e..3101aec 100644
--- a/arch/arm/boot/dts/kirkwood-ns2-common.dtsi
+++ b/arch/arm/boot/dts/kirkwood-ns2-common.dtsi
@@ -64,7 +64,7 @@
 
 		button@1 {
 			label = "Power push button";
-			linux,code = <116>;
+			linux,code = <KEY_POWER>;
 			gpios = <&gpio1 0 0>;
 		};
 	};