audio: Use only one channel for the vx pcm

Match stock setup

Change-Id: Ic72aa5280d7623fb484934268fa0a43ed7236da7
Switch to source-built hwcomposer

Change-Id: Ib676cae7e5761aa294ea6b9100d8d67667223fee
add API 0.3 support to HWC HAL.

this includes support for VSYNC

Change-Id: I14b8b133b29b0b6c825d67d18d5262843ca6bd96
hwc: add handling for new style vsync events

Change-Id: Ia435c57e0938826206010a3bdb58bcefe4201405