hammerhead: Enable USB audio

Change-Id: I83861e0c70eeeb5035f89bfa4c32f19c21236437
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
Add overlay for  config_deviceHardwareKeys

Change-Id: Ibf8b0e4ef6e53773f6ef9e4457a10101b81bf970
hammerhead: Always keep 3 buffers ready

 * Reduces overall jank system-wide

Change-Id: I37f6021237c81197063d3fd1fd7e5e07626490c9
hammerhead: Better mount options to improve performance

Change-Id: I18f7165c2ff8547b7968d946336d948fe30522b1
hammerhead: Enable offload for USB audio

Change-Id: I7cc9580865da63330a0bf54d5716ca23a2d6216c
Add support for USB OTG

Change-Id: Id5ded1d14f01e4bd126115866e0bf3bd75d5cfcb
update build fingerprint to KOT49H