* Nokia N900 audio setup

Required properties:
- compatible: Should contain "nokia,n900-audio"
- nokia,cpu-dai: phandle for the McBSP node
- nokia,audio-codec: phandles for the main TLV320AIC3X node and the
                     auxiliary TLV320AIC3X node (in this order)
- nokia,headphone-amplifier: phandle for the TPA6130A2 node
- tvout-selection-gpios: GPIO for tvout selection
- jack-detection-gpios: GPIO for jack detection
- eci-switch-gpios: GPIO for ECI (Enhancement Control Interface) switch
- speaker-amplifier-gpios: GPIO for speaker amplifier

Example:

sound {
	compatible = "nokia,n900-audio";

	nokia,cpu-dai = <&mcbsp2>;
	nokia,audio-codec = <&tlv320aic3x>, <&tlv320aic3x_aux>;
	nokia,headphone-amplifier = <&tpa6130a2>;

	tvout-selection-gpios = <&gpio2 8 GPIO_ACTIVE_HIGH>; /* 40 */
	jack-detection-gpios = <&gpio6 17 GPIO_ACTIVE_HIGH>; /* 177 */
	eci-switch-gpios = <&gpio6 22 GPIO_ACTIVE_HIGH>; /* 182 */
	speaker-amplifier-gpios = <&twl_gpio 7 GPIO_ACTIVE_HIGH>;
};