Faraday FOTG Host controller

This OTG-capable USB host controller is found in Cortina Systems
Gemini and other SoC products.

Required properties:
- compatible: should be one of:
  "faraday,fotg210"
  "cortina,gemini-usb", "faraday,fotg210"
- reg: should contain one register range i.e. start and length
- interrupts: description of the interrupt line

Optional properties:
- clocks: should contain the IP block clock
- clock-names: should be "PCLK" for the IP block clock

Required properties for "cortina,gemini-usb" compatible:
- syscon: a phandle to the system controller to access PHY registers

Optional properties for "cortina,gemini-usb" compatible:
- cortina,gemini-mini-b: boolean property that indicates that a Mini-B
  OTG connector is in use
- wakeup-source: see power/wakeup-source.txt

Example for Gemini:

usb@68000000 {
	compatible = "cortina,gemini-usb", "faraday,fotg210";
	reg = <0x68000000 0x1000>;
	interrupts = <10 IRQ_TYPE_LEVEL_HIGH>;
	clocks = <&cc 12>;
	clock-names = "PCLK";
	syscon = <&syscon>;
	wakeup-source;
};