* Atmel at91sam9g20ek wm8731 audio complex

Required properties:
  - compatible: "atmel,at91sam9g20ek-wm8731-audio"
  - atmel,model: The user-visible name of this sound complex.
  - atmel,audio-routing: A list of the connections between audio components.
  - atmel,ssc-controller: The phandle of the SSC controller
  - atmel,audio-codec: The phandle of the WM8731 audio codec
Optional properties:
  - pinctrl-names, pinctrl-0: Please refer to pinctrl-bindings.txt

Example:
sound {
	compatible = "atmel,at91sam9g20ek-wm8731-audio";
	pinctrl-names = "default";
	pinctrl-0 = <&pinctrl_pck0_as_mck>;

	atmel,model = "wm8731 @ AT91SAMG20EK";

	atmel,audio-routing =
		"Ext Spk", "LHPOUT",
		"Int MIC", "MICIN";

	atmel,ssc-controller = <&ssc0>;
	atmel,audio-codec = <&wm8731>;
};
