* Audio codec controlled by ChromeOS EC

Google's ChromeOS EC codec is a digital mic codec provided by the
Embedded Controller (EC) and is controlled via a host-command interface.

An EC codec node should only be found as a sub-node of the EC node (see
Documentation/devicetree/bindings/mfd/cros-ec.txt).

Required properties:
- compatible: Must contain "google,cros-ec-codec"
- #sound-dai-cells: Should be 1. The cell specifies number of DAIs.
- max-dmic-gain: A number for maximum gain in dB on digital microphone.

Example:

cros-ec@0 {
	compatible = "google,cros-ec-spi";

	...

	cros_ec_codec: ec-codec {
		compatible = "google,cros-ec-codec";
		#sound-dai-cells = <1>;
		max-dmic-gain = <43>;
	};
};