Mediatek/Ralink USB PHY

Required properties:
 - compatible: "ralink,rt3352-usbphy"
	       "mediatek,mt7620-usbphy"
	       "mediatek,mt7628-usbphy"
 - reg: required for "mediatek,mt7628-usbphy", unused otherwise
 - #phy-cells: should be 0
 - ralink,sysctl: a phandle to a ralink syscon register region
 - resets: the two reset controllers for host and device
 - reset-names: the names of the 2 reset controllers

Example:

usbphy: phy {
	compatible = "mediatek,mt7628-usbphy";
	reg = <0x10120000 0x1000>;
	#phy-cells = <0>;

	ralink,sysctl = <&sysc>;
	resets = <&rstctrl 22 &rstctrl 25>;
	reset-names = "host", "device";
};