ath79: qihoo,c301: use phy-supply for usb vbus

Linux phy subsystem provides support for a phy regulator defined via
phy-supply property. Use it to turn on usb power only when usb is
probed.

Signed-off-by: Chuanhong Guo <gch981213@gmail.com>

target/linux/ath79/dts/ar9344_qihoo_c301.dts

@@ -52,13 +52,12 @@
 		gpio = <&gpio 18 GPIO_ACTIVE_LOW>;
 	};
 
-	reg_usb_vbus {
+	usb_vbus: reg_usb_vbus {
 		compatible = "regulator-fixed";
 		regulator-name = "usb_vbus";
 		regulator-min-microvolt = <5000000>;
 		regulator-max-microvolt = <5000000>;
 		enable-active-high;
-		regulator-always-on;
 		gpio = <&gpio 19 GPIO_ACTIVE_HIGH>;
 	};
 };
@@ -202,6 +201,7 @@
 
 &usb_phy {
 	status = "okay";
+	phy-supply = <&usb_vbus>;
 };
 
 &pcie {