ASoC: msm: Do not allow commands during gapless transition

During gapless playback if flush is sent to the driver before EOS
acknowledgement from DSP, the playback is switched to stream one.
On EOS ack the stream one is closed resulting in no audio. The fix
is to not allow pause/resume/flush commands during transition from
one clip to other during gapless playback. Playback should move to
the second stream if the playback enters transition period.

CRs-Fixed: 588353
Change-Id: I1be30956cce677e153ef5b8a362de303fec7620a
Signed-off-by: Krishnankutty Kolathappilly <kkolat@codeaurora.org>