ARM: dts: Add gpio-button entries for Arndale board

Added GPIO buttons DT node to Arndale board file.
Signed-off-by: Tushar Behera <tushar.behera@linaro.org>
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

arch/arm/boot/dts/exynos5250-arndale.dts

@@ -116,6 +116,52 @@ spi_2: spi@12d40000 {
 		status = "disabled";
 	};
 
+	gpio_keys {
+		compatible = "gpio-keys";
+
+		menu {
+			label = "SW-TACT2";
+			gpios = <&gpx1 4 1>;
+			linux,code = <139>;
+			gpio-key,wakeup;
+		};
+
+		home {
+			label = "SW-TACT3";
+			gpios = <&gpx1 5 1>;
+			linux,code = <102>;
+			gpio-key,wakeup;
+		};
+
+		up {
+			label = "SW-TACT4";
+			gpios = <&gpx1 6 1>;
+			linux,code = <103>;
+			gpio-key,wakeup;
+		};
+
+		down {
+			label = "SW-TACT5";
+			gpios = <&gpx1 7 1>;
+			linux,code = <108>;
+			gpio-key,wakeup;
+		};
+
+		back {
+			label = "SW-TACT6";
+			gpios = <&gpx2 0 1>;
+			linux,code = <158>;
+			gpio-key,wakeup;
+		};
+
+		wakeup {
+			label = "SW-TACT7";
+			gpios = <&gpx2 1 1>;
+			linux,code = <143>;
+			gpio-key,wakeup;
+		};
+	};
+
 	fixed-rate-clocks {
 		xxti {
 			compatible = "samsung,clock-xxti";