msm: mdss: reset panel when wait4pingpong timeout is received

Due to various reasons wait4pingpong timeout can be observed and
this usually results in split screen behaviour for the end user.
Split screen is manifested because for a given frame only half of
the pixel data was sent and then some kind of hang was observed.
So unless the panel and display pipeline is restarted, next frames
will start from the location where it hanged. Improve user behavior
by resetting the display pipeline including panel by sending panel
dead event to user-space. Upon receiving this event user-space should
issue blank and un-blank which should recover the display pipeline.

Change-Id: Iec674a61229cbc037d24cf4f62ceb02a977b219c
Signed-off-by: Ujwal Patel <ujwalp@codeaurora.org>
Signed-off-by: Naseer Ahmed <naseer@codeaurora.org>
Signed-off-by: Jeevan Shriram <jshriram@codeaurora.org>