ASoC: Zoom2: Add machine driver for Zoom2 board

Add support for Zoom2 board. Zoom2 machine driver
connects both codec DAIs (audio and voice) to omap3
McBSP ports in the following way:

  HiFi <-> McBSP2
 Voice <-> McBSP3

The zoom2 driver has the following DAPM widgets:
* Ext Mic: MAINMIC, SUBMIC (with bias)
* Ext Spk: HFL, HFR
* Headset Stereophone: HSOL, HSOR
* Headset Mic: HSMIC (with bias)
* Aux In: AUXL, AUXR

Signed-off-by: Misael Lopez Cruz <x0052729@ti.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>