Freescale i.MX audio complex with MAX98088/MAX98089 codec

Required properties:
- compatible : "fsl,imx-audio-max98088","fsl,imx-audio-max98089"
- model : The user-visible name of this sound complex
- cpu-dai : The phandle of CPU dai
- gpr : The phandle of i.MX IOMUXC GPR for managing SAI MCLK
- audio-codec : The phandle of the MAX98088/MAX98089 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, MAX98088/MAX98089 pins, and the jacks on the board.

  e.g. Board connectors:
   * Headphone Jack
   * Ext Spk
   * Mic1
   * Mic2
   * LineInA
   * LineInB
   * LineOut

Not implemented:
- Regulators for power supplies
- Interrupt handling
- Jack detection (JACKSNS)

Example:

sound {
        compatible = "fsl,imx-audio-max98088";
        model = "imx-max98088";
        cpu-dai = <&ssi2>;
        gpr = <&gpr>;
        audio-codec = <&codec>;
        audio-routing =
                "Headphone Jack","HPL",
                "Headphone Jack","HPR",
                "Ext Spk","SPKL",
                "Ext Spk","SPKR";
};
