Freescale i.MX audio complex with AK5558 ADC

Required properties:

- compatible	: "fsl,imx-audio-ak5558"
- model		: The user-visible name of this sound complex
- audio-cpu	: The phandle of CPU DAI
- audio-codec	: The phandle of the AK5558 audio ADC
- 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, AK5558 pins,
  and the jacks on the board.

Example:

sound {
       compatible = "fsl,imx-audio-ak5558";
       model = "ak5558-audio";
       audio-cpu = <&sai1>;
       audio-codec = <&codec>;
       audio-routing =
               "AIN1", "Capture",
               "AIN2", "Capture",
               "AIN3", "Capture",
               "AIN4", "Capture",
               "AIN5", "Capture",
               "AIN6", "Capture",
               "AIN7", "Capture",
               "AIN8", "Capture";
};