ASoC: msm: qdsp6v2: Wait for stream to be available in gapless playback

Compressed driver operates on two streams in gapless mode and switches
between the two streams. If compressed playback operates on larger
buffers and the clip being played is small enough to fit in one
buffer, the driver could run into a scenario where three streams
need to be handled. Three streams results in no audio because stream
switching logic is corrupted. Fix is to block the next track call if
stream one has not completed playback.

CRs-Fixed: 594977
Change-Id: I6c83e859fa38f177ec7f4fa4ea92937d34df933a
Signed-off-by: Krishnankutty Kolathappilly <kkolat@codeaurora.org>