ASoC: msm: qdsp6v2: fix callback handling of removing silence cmds

Remove silence cmds don't have wait function so no need to wake up any
thread. Unnecessary wake_up cause the change of command order which ends
up with instability. In addition fix missing mutex_unlock after adm_open
failure.

CRs-fixed: 777738
Signed-off-by: Fred Oh <fred@codeaurora.org>
Change-Id: Id04cafb64a9859b75ba975523f4ef28e623f218b