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
Revert "Temp: disable WiDi"

This reverts commit ad5622ff548929005dcede5aca83c450d23fb716.
Both G and GK are now functional