ASoC: msm: Add reference count to audio calibration driver

Add reference count to audio calibration driver used
to make sure all clients are closed before telling
all kernel calibration clients to free their calibration
buffers. Adds common mutex used to saftely alter
reference count.

Change-Id: Ib51e0c6fbb5fcfac1457580589fa624fb757146d
Signed-off-by: Ben Romberger <bromberg@codeaurora.org>