ASoC: compress: Update lock for dpcm calls

Compress driver calls into the dpcm framework when
usecase is started/stopped.When calling dpcm framework
api's it should acquire dpcm mutex.
This change replaces the card mutex with dpcm mutex when
dpcm apis are called.

CRs-fixed: 596103
Change-Id: I66abb823e07a0d7eb5d9687927526d785959410f
Signed-off-by: Gopikrishnaiah Anandan <agopik@codeaurora.org>
ASoC: Compress: Remove unused hw_params pointer

Remove the hw_params variable in
soc_compr_set_params_fe as the memory allocated
for it was not freed and the pointer itself was
not used.

CRs-Fixed: 601556
Change-Id: If2abfe58ad6dedab9b7ba21ae6f3b4bb5335cf42
Signed-off-by: Kenneth Westfield <kwestfie@codeaurora.org>