msm: mdss: Handle case when pipe is not idle during cleanup.

When pipe is not idle during cleanup, MDP can go into an unrecoverable
state, which can lead into other issues. If it gets to this point we
need to recover even if it means changing display contents for a
fraction of time. To handle this follow recovery sequence:
1. Setup the pipes that are not idle to solid fill mode so that nothing
   is fetched from memory on these pipes.
2. Stage them into mixer, flush and wait for a vsync to happen and reset
   sequence to take effect on these.
3. Finally, reattach the current frame pipes to restore display back to
   normal.

Signed-off-by: Jayant Shekhar <jshekhar@codeaurora.org>
Signed-off-by: Adrian Salido-Moreno <adrianm@codeaurora.org>

Conflicts:
	drivers/video/msm/mdss/mdss_mdp_overlay.c

Change-Id: I32cdd159651b995a1a857da8d8aa191511bf9893