drm/msm/dsi-staging: support dynamic frame-rate and validation

Sanitize for seamless frame-rate transitions for dynamic FPS. Check
for proper video timings, controller operation states etc.

Change-Id: I5f29238861e9bad41e7bac9f34cda12c29174868
Signed-off-by: Ajay Singh Parmar <aparmar@codeaurora.org>