ASoC: msm: q6: move ocmem enable request from trigger to open

OCMEM mapping needs to be done only once for multiple tunnel
instances, we vote and unvote when a compressed session is
open and closed to make above happen. But this voting and
enable ocmem call was being made in msm_compr_trigger, need to
move this to msm_compr_open

Change-Id: I3e0f78d7c57c2a17e69320fdcc447e38aeca0805
Signed-off-by: Jitendra Singh Naruka <jnaruk@codeaurora.org>