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

Change-Id: I53ea537072b2bbe95325ec79871302bdcc9c9f04
tree: 547529416ecbc3c2a89ba3197d28f090fb46f1af
  1. hal/
  2. legacy/
  3. post_proc/
  4. visualizer/
  5. voice_processing/
  6. Android.mk