Audio complex for Eukrea boards with tlv320aic23 codec.

Required properties:
- compatible : "eukrea,asoc-tlv320"
- eukrea,model : The user-visible name of this sound complex.
- ssi-controller : The phandle of the SSI controller.
- fsl,mux-int-port : The internal port of the i.MX audio muxer (AUDMUX).
- fsl,mux-ext-port : The external port of the i.MX audio muxer.

Note: The AUDMUX port numbering should start at 1, which is consistent with
hardware manual.

Example:

	sound {
		compatible = "eukrea,asoc-tlv320";
		eukrea,model = "imx51-eukrea-tlv320aic23";
		ssi-controller = <&ssi2>;
		fsl,mux-int-port = <2>;
		fsl,mux-ext-port = <3>;
	};