ASoC: msm: Register restart api for under run issue.

Update compressed platform driver to register an restart callback.
Implementation of the restart callback is to issue an pending buffer
Written by application to restart the session when  the de queue
Process is stopped due to underrun issue.

Restart callback is triggered from the ALSA core framework when
Framework detects that the render stopped pulling the data
And application is writtig the data.

This callback will be running in atomic context.

Change-Id: Iada382f39bd052beeb0b1d165959d510fa51ff7c
Signed-off-by: Santosh Mardi <gsantosh@codeaurora.org>

Conflicts:
	sound/soc/msm/msm-compr-q6.c