sthal: buffer ref count incorrect cause routing unbalance

note: If the crash happens during handle voice-call case, setup
      buffer had some trouble. Then the reference count will be
      unbalance. The abnormal audio_route setup would happen and
      can't recovery until reboot.

Bug: 138557656
Test: manual simulate the same sequence to verify
Change-Id: I2c35b7a06869a5355bd742da5d53df2e6075d1cd
1 file changed