* Samsung's usb phy transceiver

The Samsung's phy transceiver is used for controlling usb phy for
s3c-hsotg as well as ehci-s5p and ohci-exynos usb controllers
across Samsung SOCs.
TODO: Adding the PHY binding with controller(s) according to the under
developement generic PHY driver.

Required properties:

Exynos4210:
- compatible : should be "samsung,exynos4210-usbphy"
- reg : base physical address of the phy registers and length of memory mapped
	region.

Exynos5250:
- compatible : should be "samsung,exynos5250-usbphy"
- reg : base physical address of the phy registers and length of memory mapped
	region.

Optional properties:
- #address-cells: should be '1' when usbphy node has a child node with 'reg'
		  property.
- #size-cells: should be '1' when usbphy node has a child node with 'reg'
	       property.
- ranges: allows valid translation between child's address space and parent's
	  address space.

- The child node 'usbphy-sys' to the node 'usbphy' is for the system controller
  interface for usb-phy. It should provide the following information required by
  usb-phy controller to control phy.
  - reg : base physical address of PHY_CONTROL registers.
	  The size of this register is the total sum of size of all PHY_CONTROL
	  registers that the SoC has. For example, the size will be
	  '0x4' in case we have only one PHY_CONTROL register (e.g.
	  OTHERS register in S3C64XX or USB_PHY_CONTROL register in S5PV210)
	  and, '0x8' in case we have two PHY_CONTROL registers (e.g.
	  USBDEVICE_PHY_CONTROL and USBHOST_PHY_CONTROL registers in exynos4x).
	  and so on.

Example:
 - Exynos4210

	usbphy@125B0000 {
		#address-cells = <1>;
		#size-cells = <1>;
		compatible = "samsung,exynos4210-usbphy";
		reg = <0x125B0000 0x100>;
		ranges;

		usbphy-sys {
			/* USB device and host PHY_CONTROL registers */
			reg = <0x10020704 0x8>;
		};
	};