drm/msm/sde: handle missing ctl_start interrupt for retire fence

MDP hardware triggers the ctl_start interrupt on
frame transfer start. SW triggers the retire fence
on this interrupt to allow buffer flip. HW may miss
to trigger this interrupt for some unknown scenario. SW
needs to still trigger the interrupt on pingpong boundary
to avoid retire fence signal failure.

Change-Id: Ibed64fa8a88d666ada40db38e8a8fe76dd4050a3
Signed-off-by: Dhaval Patel <pdhaval@codeaurora.org>