TI Keystone USB PHY

Required properties:
 - compatible: should be "ti,keystone-usbphy".
 - #address-cells, #size-cells : should be '1' if the device has sub-nodes
   with 'reg' property.
 - reg : Address and length of the usb phy control register set.

The main purpose of this PHY driver is to enable the USB PHY reference clock
gate on the Keystone SOC for both the USB2 and USB3 PHY. Otherwise it is just
an NOP PHY driver.  Hence this node is referenced as both the usb2 and usb3
phy node in the USB Glue layer driver node.

usb_phy: usb_phy@2620738 {
	compatible = "ti,keystone-usbphy";
	#address-cells = <1>;
	#size-cells = <1>;
	reg = <0x2620738 32>;
	status = "disabled";
};
