asoc: mixer control queue handling in sink stream

Mixer control queue handling is required only for
playback. Move mixer control queue handling to be
part of the playback stream in DSP transcode loopback
driver.

Change-Id: Ia8067237f80d509f969cf454f5afa08aaa6b0e52
Signed-off-by: Siddartha Shaik <sshaik@codeaurora.org>
Signed-off-by: Surendar Karka <skarka@codeaurora.org>