disp: msm: sde: handle another case for lost pp-done interrupt

Due to interrupt delays, sometimes the pp-done interrupt
for an in-between frame is lost, as with posted-start
frames are queued to the hardware before the completion
of the previous frame. Handle the lost pp-done interrupt
in the case where frame-n pp-done interrupt is missed
and frame-n+1 pp-done interrupt is processed before
frame-n+1 wr-ptr interrupt.

Change-Id: I36ec7ac494b2720fc005dab75047d2f4a5a2a699
Signed-off-by: Veera Sundaram Sankaran <veeras@codeaurora.org>