Revert "hal: add support to separate headset and headphones mixer backend" am: 509f0a7cc7
am: 70e62baecc

Change-Id: Ic609fb17f3d7273d9385daa6783a87147349fc17
tree: 5b36de4efe0bb16e21a99b394fed1a0568fc0a41
  1. hal/
  2. legacy/
  3. post_proc/
  4. visualizer/
  5. voice_processing/
  6. Android.mk