drm/msm/sde: update dest scalar status after mixer setup

DRM client may set destination scalar enable property with valid
lut configuration along with first CRTC enable frame. Mixers are not
allocated at this point and destination scalar returns early during
setup call. That triggers first frame without destination scalar followed
by destination scalar enabled on second frame. This change adds
destination scalar status update after mixer setup to allow first frame
trigger with DS enabled state. The updated sequence also non-double
buffered DS QSEED LUT update when video mode frame transfer is in-progress.

Change-Id: Ic63eeca02f994090a45fedb00b6ee12d5e46629e
Signed-off-by: Narendra Muppalla <NarendraM@codeaurora.org>