audio: free and assign NULL to global static device pointer
am: 73d6b59977

Change-Id: I44632c224c6ee9edca73fda24593362379220fff
tree: f90d96ca6cd22796eb191e886167942b4b311cae
  1. hal/
  2. legacy/
  3. post_proc/
  4. visualizer/
  5. voice_processing/
  6. Android.mk
  7. OWNERS