ARM: bcm2835: Add the Raspberry Pi power domain driver to the DT.

This connects the USB driver to the USB power domain, so that USB can
actually be turned on at boot if the bootloader didn't do it for us.

Signed-off-by: Alexander Aring <[e-mail]>
Signed-off-by: Eric Anholt <[e-mail]>
Reviewed-by: Kevin Hilman <[e-mail]>

arch/arm/boot/dts/bcm2835-rpi.dtsi

···
+#include <dt-bindings/power/raspberrypi-power.h>
+
 / {
 	memory {
 		reg = <0 0x10000000>;
···
 		firmware: firmware {
 			compatible = "raspberrypi,bcm2835-firmware";
 			mboxes = <&mailbox>;
+		};
+
+		power: power {
+			compatible = "raspberrypi,bcm2835-power";
+			firmware = <&firmware>;
+			#power-domain-cells = <1>;
 		};
 	};
 };
···
 
 &pwm {
 	status = "okay";
+};
+
+&usb {
+	power-domains = <&power RPI_POWER_DOMAIN_USB>;
 };

arch/arm/boot/dts/bcm283x.dtsi

···
 			status = "disabled";
 		};
 
-		usb@7e980000 {
+		usb: usb@7e980000 {
 			compatible = "brcm,bcm2835-usb";
 			reg = <0x7e980000 0x10000>;
 			interrupts = <1 9>;