Freescale i.MX audio complex with SGTL5000 codec

Required properties:

  - compatible		: "fsl,imx-audio-sgtl5000"

  - model		: The user-visible name of this sound complex

  - ssi-controller	: The phandle of the i.MX SSI controller

  - audio-codec		: The phandle of the SGTL5000 audio codec

  - audio-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. Valid names could be power supplies, SGTL5000
			  pins, and the jacks on the board:

			  Power supplies:
			   * Mic Bias

			  SGTL5000 pins:
			   * MIC_IN
			   * LINE_IN
			   * HP_OUT
			   * LINE_OUT

			  Board connectors:
			   * Mic Jack
			   * Line In Jack
			   * Headphone Jack
			   * Line Out Jack
			   * Ext Spk

  - mux-int-port	: The internal port of the i.MX audio muxer (AUDMUX)

  - 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 = "fsl,imx51-babbage-sgtl5000",
		     "fsl,imx-audio-sgtl5000";
	model = "imx51-babbage-sgtl5000";
	ssi-controller = <&ssi1>;
	audio-codec = <&sgtl5000>;
	audio-routing =
		"MIC_IN", "Mic Jack",
		"Mic Jack", "Mic Bias",
		"Headphone Jack", "HP_OUT";
	mux-int-port = <1>;
	mux-ext-port = <3>;
};