audio: Increase the period size for USB audio

 -During USB audio playback, breaks are heard .This is
  primarily due to overruns of USB buffer from the audio
  HAL.
 -By increasing the period size of USB buffer we are
  avoiding overruns .

  CRs-Fixed: 574897

Change-Id: I78fb1bd5d7201fe789a2fcc5090eb1555af408ea
audio: Add support for AUXPCM BT

Atheros BT chip uses AUXPCM instead of slimbus. Audio HAL has
to use different UCM files depending on whether it's
internal or external BT chip

Change-Id: If6580ea1608b9dc8bb24be58dd2c4d2bbc331f92