ARM: orion5x: use gpio-keys and gpio-leds instead of gpio_keys/gpio_leds in edmini_v2

As noted by Sebastian Hesselbarth, the Device Tree nodes for GPIO keys
and LEDs should be named gpio-keys and gpio-leds.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Link: https://lkml.kernel.org/r/1398202002-28530-16-git-send-email-thomas.petazzoni@free-electrons.comSigned-off-by: Jason Cooper <jason@lakedaemon.net>

arch/arm/boot/dts/orion5x-lacie-ethernet-disk-mini-v2.dts

@@ -41,7 +41,7 @@ sata@80000 {
 		};
 	};
 
-	gpio_keys {
+	gpio-keys {
 		compatible = "gpio-keys";
 		#address-cells = <1>;
 		#size-cells = <0>;
@@ -52,7 +52,7 @@ button@1 {
 		};
 	};
 
-	gpio_leds {
+	gpio-leds {
 		compatible = "gpio-leds";
 
 		led@1 {