ARM: Kirkwood: Describe IB62x0 gpio-keys in DT.

Now that the GPIO controllers have been converted over to DT,
described the gpio-keys in DT.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Simon Baatz <gmbnomis@gmail.com>

arch/arm/boot/dts/kirkwood-ib62x0.dts

@@ -46,4 +46,20 @@
 
 		};
 	};
+
+	gpio_keys {
+		compatible = "gpio-keys";
+		#address-cells = <1>;
+		#size-cells = <0>;
+		button@1 {
+			label = "USB Copy";
+			linux,code = <133>;
+			gpios = <&gpio0 29 1>;
+		};
+		button@2 {
+			label = "Reset";
+			linux,code = <0x198>;
+			gpios = <&gpio0 28 1>;
+		};
+	};
 };