dt-bindings: add binding for Rockchip hdmi phy using an Innosilicon IP

ROCKCHIP HDMI PHY WITH INNO IP BLOCK

Required properties:

 - compatible : should be one of the listed compatibles:

	* "rockchip,rk3228-hdmi-phy",

	* "rockchip,rk3328-hdmi-phy";

 - reg : Address and length of the hdmi phy control register set

 - clocks : phandle + clock specifier for the phy clocks

 - clock-names : string, clock name, must contain "sysclk" for system

	  control and register configuration, "refoclk" for crystal-

	  oscillator reference PLL clock input and "refpclk" for pclk-

	  based refeference PLL clock input.

 - #clock-cells: should be 0.

 - clock-output-names : shall be the name for the output clock.

 - interrupts : phandle + interrupt specified for the hdmiphy interrupt

 - #phy-cells : must be 0. See ./phy-bindings.txt for details.

Optional properties for rk3328-hdmi-phy:

 - nvmem-cells = phandle + nvmem specifier for the cpu-version efuse

 - nvmem-cell-names : "cpu-version" to read the chip version, required

	  for adjustment to some frequency settings

Example:

	hdmi_phy: hdmi-phy@12030000 {

		compatible = "rockchip,rk3228-hdmi-phy";

		reg = <0x12030000 0x10000>;

		#phy-cells = <0>;

		clocks = <&cru PCLK_HDMI_PHY>, <&xin24m>, <&cru DCLK_HDMIPHY>;

		clock-names = "sysclk", "refoclk", "refpclk";

		#clock-cells = <0>;

		clock-output-names = "hdmi_phy";

		status = "disabled";

	};

Then the PHY can be used in other nodes such as:

	hdmi: hdmi@200a0000 {

		compatible = "rockchip,rk3228-dw-hdmi";

		...

		phys = <&hdmi_phy>;

		phy-names = "hdmi";

		...

	};