Prevent leak of sndmonitor resources

During vts tests, the audio primary hal interface is queried and release
more than 600 times.
This patch avoids leaking sndmonitors when initializing and
deinitializing the qcom hal repeatedly in the same process.

Test: play music and phone call
Bug: 36311550

Change-Id: I9b3de1f11afd50fbd824155516c6adecd073ee83
Signed-off-by: Kevin Rocard <krocard@google.com>