ASoC: msm: Fix device suspend crash

Device is crashed while suspend because of calling
mutex_lock multiple times without unlock. Fix by
calling mutex_unlock properly

Change-Id: I90f151dd4b1adb7bf7600be1ef980be206a190b1
Signed-off-by: Vidyakumar Athota <vathota@codeaurora.org>
CRs-Fixed: 594736