ARM: Kirkwood: Convert NS2 to gpio-poweroff.

Remove C code and add a Device Tree node in its place.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Simon Guinot <simon.guinot@sequanux.org>
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 77d21ab..e8e7ece 100644
--- a/arch/arm/boot/dts/kirkwood-ns2-common.dtsi
+++ b/arch/arm/boot/dts/kirkwood-ns2-common.dtsi
@@ -76,4 +76,10 @@
 			gpios = <&gpio0 12 0>;
 		};
 	};
+
+	gpio_poweroff {
+		compatible = "gpio-poweroff";
+		gpios = <&gpio0 31 0>;
+	};
+
 };