ASoC: msm8x16-wcd: update codec driver to unlock mutex properly

Update codec driver to unlock the mutex before returning during
error case.

Update machine driver not to decrement the mclk reference counter
before disabling the mclk, the reference counter should be
decremented after the mclk disable is completed

CRs-Fixed: 646358
Change-Id: Icf6c3463c7b4e1e45a643c66add3b7685093263c
Signed-off-by: Santosh Mardi <gsantosh@codeaurora.org>