ROCKCHIP RK3288 with HDMI and analog audio

Required properties:
- compatible: "rockchip,rk3288-hdmi-analog"
- 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
- rockchip,audio-codec: The phandle of the analog audio codec.
- rockchip,routing: A list of the connections between audio components.
		    Each entry is a pair of strings, the first being the
		    connection's sink, the second being the connection's
		    source. For this driver the first string should always be
		    "Analog".

Optionnal properties:
- rockchip,hp-en-gpios = The phandle of the GPIO that power up/down the
  headphone (when the analog output is an headphone).
- rockchip,hp-det-gpios = The phandle of the GPIO that detects the headphone
  (when the analog output is an headphone).
- pinctrl-names, pinctrl-0: Please refer to pinctrl-bindings.txt

Example:

sound {
	compatible = "rockchip,rk3288-hdmi-analog";
	rockchip,model = "Analog audio output";
	rockchip,i2s-controller = <&i2s>;
	rockchip,audio-codec = <&es8388>;
	rockchip,routing = "Analog", "LOUT2",
			   "Analog", "ROUT2";
	rockchip,hp-en-gpios = <&gpio8 0 GPIO_ACTIVE_HIGH>;
	rockchip,hp-det-gpios = <&gpio7 7 GPIO_ACTIVE_HIGH>;
	pinctrl-names = "default";
	pinctrl-0 = <&headphone>;
};