hal: post_proc: add volume based audio calibration support

- add new effect module to listen to volume and device change
- based on volume levels of all streams active over speaker
  compute gain based calibration level and communicate
  with audio HAL to send the same to ACDB loader
- make audio HAL singleton

Bug: 22100304.

Change-Id: If74bf66d32def85022d79ccb9f84c3b85c8a2dc9
6 files changed
tree: 39ac31ebf1a9bca2d79ff4a1e237d21e2a442efe
  1. hal/
  2. legacy/
  3. post_proc/
  4. visualizer/
  5. voice_processing/
  6. Android.mk