USB OHCI controllers

Required properties:
- compatible : "generic-ohci"
- reg : ohci controller register range (address and length)
- interrupts : ohci controller interrupt

Optional properties:
- big-endian-regs : boolean, set this for hcds with big-endian registers
- big-endian-desc : boolean, set this for hcds with big-endian descriptors
- big-endian : boolean, for hcds with big-endian-regs + big-endian-desc
- no-big-frame-no : boolean, set if frame_no lives in bits [15:0] of HCCA
- num-ports : u32, to override the detected port count
- clocks : a list of phandle + clock specifier pairs
- phys : phandle + phy specifier pair
- phy-names : "usb"
- resets : phandle + reset specifier pair

Example:

	ohci0: usb@01c14400 {
		compatible = "allwinner,sun4i-a10-ohci", "generic-ohci";
		reg = <0x01c14400 0x100>;
		interrupts = <64>;
		clocks = <&usb_clk 6>, <&ahb_gates 2>;
		phys = <&usbphy 1>;
		phy-names = "usb";
	};