* Freescale MXS USB Phy Device

Required properties:
- compatible: should contain:
	* "fsl,imx23-usbphy" for imx23 and imx28
	* "fsl,imx6q-usbphy" for imx6dq and imx6dl
	* "fsl,imx6sl-usbphy" for imx6sl
	* "fsl,vf610-usbphy" for Vybrid vf610
	* "fsl,imx6sx-usbphy" for imx6sx
	* "fsl,imx6ul-usbphy" for imx6ul
	* "fsl,imx7ulp-usbphy" for imx7ulp
  "fsl,imx23-usbphy" is still a fallback for other strings
- reg: Should contain registers location and length
- interrupts: Should contain phy interrupt
- fsl,anatop: phandle for anatop register, it is only for imx6 SoC series

Optional properties:
- fsl,tx-cal-45-dn-ohms: Integer [30-55]. Resistance (in ohms) of switchable
  high-speed trimming resistor connected in parallel with the 45 ohm resistor
  that terminates the DN output signal. Default: 45
- fsl,tx-cal-45-dp-ohms: Integer [30-55]. Resistance (in ohms) of switchable
  high-speed trimming resistor connected in parallel with the 45 ohm resistor
  that terminates the DP output signal. Default: 45
- fsl,tx-d-cal: Integer [79-119]. Current trimming value (as a percentage) of
  the 17.78mA TX reference current. Default: 100
- tx-d-cal: Try to adjust this value to improve signal quality, and pass
  USB Certification, the value is from 0x0 to 0xf, and the register offset
  is 0x10 (USBPHY_TX).

Example:
usbphy1: usbphy@020c9000 {
	compatible = "fsl,imx6q-usbphy", "fsl,imx23-usbphy";
	reg = <0x020c9000 0x1000>;
	interrupts = <0 44 0x04>;
	fsl,anatop = <&anatop>;
	tx-d-cal = <0x5>;
};