hammerhead: Better USB audio support

 * Use new QCOM USB audio path which uses the AFE proxy.
 * This fixes the issues with skips and drops when UI sounds play.

Change-Id: I9941d49b669208959353805f43f51874a415eba3
hammerhead: Enable offload for USB audio

Change-Id: I7cc9580865da63330a0bf54d5716ca23a2d6216c
Add support for USB OTG

Change-Id: Id5ded1d14f01e4bd126115866e0bf3bd75d5cfcb