Enable USB audio adapters

This'll only work for variants with OTG (the K models), the rest
will remain unable to power the DAC.

Change-Id: I6af787f5d4f239fddc521c0ad59b2d72400cd13d
Merge branch 'cm-11.0' of git://github.com/CyanogenMod/android_device_lge_gproj-common into kk4.4