ARM: dts: imx51-zii-rdu1: add rave-sp subdevices

This adds rave-sp powerbutton and backlight devices to RDU1 device tree.
Signed-off-by: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
Tested-by: Chris Healy <cphealy@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/imx51-zii-rdu1.dts

@@ -582,6 +582,14 @@ rave-sp {
 		watchdog {
 			compatible = "zii,rave-sp-watchdog";
 		};
+
+		backlight {
+			compatible = "zii,rave-sp-backlight";
+		};
+
+		pwrbutton {
+			compatible = "zii,rave-sp-pwrbutton";
+		};
 	};
 };