ASoC: dsp: Synchronise adm commands

Race condition observed while processing the
get/set_pp_params and adm_close command.
Synchronise adm open, close and get/set_pp_params
by sending the apr cmd pkt using the same lock.

Change-Id: I9a1ebcedc91f78f3940846688f8569ec9088e1e7
Signed-off-by: Soumya Managoli <smanag@codeaurora.org>