audio: free and assign NULL to global static device pointer

Free and assign NULL to global static device pointer instead of local
pointer to avoid free after use issue.

Bug: 144583303
Signed-off-by: Harrison Lingren <hlingren@google.com>

Change-Id: Idfdef719320efcd792c7d2ebd7ec2dfe5d3fbfbd
1 file changed
tree: 8bfe7ea441bccda633f4c8cfb434fdb080c7b495
  1. hal/
  2. legacy/
  3. post_proc/
  4. visualizer/
  5. voice_processing/
  6. Android.mk
  7. OWNERS