linux-phytec-ti

drm/msm/mdp: Clear pending interrupt status before enable interrupt

Pending interrupt status needs to be cleared before enable the
interrupt. Otherwise it's possible to get a pending interrupt instead
of an incoming interrupt.

Signed-off-by: Jilai Wang <jilaiw@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>