ROCKCHIP with MAX98090 CODEC

Required properties:
- compatible: "rockchip,rockchip-audio-max98090"
- rockchip,model: The user-visible name of this sound complex
- rockchip,i2s-controller: The phandle of the Rockchip I2S controller that's
  connected to the CODEC

Optional properties:
- rockchip,audio-codec: The phandle of the MAX98090 audio codec.
- rockchip,headset-codec: The phandle of Ext chip for jack detection. This is
                          required if there is rockchip,audio-codec.
- rockchip,hdmi-codec: The phandle of HDMI device for HDMI codec.

Example:

/* For max98090-only board. */
sound {
	compatible = "rockchip,rockchip-audio-max98090";
	rockchip,model = "ROCKCHIP-I2S";
	rockchip,i2s-controller = <&i2s>;
	rockchip,audio-codec = <&max98090>;
	rockchip,headset-codec = <&headsetcodec>;
};

/* For HDMI-only board. */
sound {
	compatible = "rockchip,rockchip-audio-max98090";
	rockchip,model = "ROCKCHIP-I2S";
	rockchip,i2s-controller = <&i2s>;
	rockchip,hdmi-codec = <&hdmi>;
};

/* For max98090 plus HDMI board. */
sound {
	compatible = "rockchip,rockchip-audio-max98090";
	rockchip,model = "ROCKCHIP-I2S";
	rockchip,i2s-controller = <&i2s>;
	rockchip,audio-codec = <&max98090>;
	rockchip,headset-codec = <&headsetcodec>;
	rockchip,hdmi-codec = <&hdmi>;
};
