hal: add support to separate headset and headphones mixer backend
am: 6c5e87cca3

Change-Id: Ie86a0ac935382f0a20046e2b6262d1bca7659726
tree: fa1b82c2dc189a22c15172f41ca6f379df2fc8db
  1. hal/
  2. legacy/
  3. post_proc/
  4. visualizer/
  5. voice_processing/
  6. Android.mk