WM8750 and WM8987 audio CODECs

These devices support both I2C and SPI (configured with pin strapping
on the board).

Required properties:

  - compatible : "wlf,wm8750" or "wlf,wm8987"

  - reg : the I2C address of the device for I2C, the chip select
          number for SPI.

Example:

codec: wm8750@1a {
	compatible = "wlf,wm8750";
	reg = <0x1a>;
};