asoc: add support to set ADM channels for SLIM_9_TX port

In split A2DP sink ADM channels is set to mono based
on BE config. Add support to set ADM channels based
on decoder config received from BT IPC library.

Change-Id: I3925b805593871d420f4cfd3ce4b87adb0e03272
Signed-off-by: Surendar Karka <skarka@codeaurora.org>