hal: support HFP volume mixer in audio platform info

Add support to get HFP volume mixer control from
audio_platform_info.xml.

Bug: 29971368

Change-Id: I6f3a718ccaf2518826c756d043204165a19ca820
2 files changed
tree: 76692d8b3a9502da4aa1fbaadd8caf7f3bad8c9d
  1. hal/
  2. legacy/
  3. post_proc/
  4. visualizer/
  5. voice_processing/
  6. Android.mk