drm/msm/sde: avoid partial update when DS is enabled

Partial Update and Destination Scaler concurrency is not supported on
sde. This change will revert DS standalone check, because concurrency
validation is evaluated by crtc while setting layer mixer ROI.

Change-Id: I66e7ea18e8a4b5780ab0988e5841aafecaf0dae8
Signed-off-by: Ch Ganesh Kumar <chganesh@codeaurora.org>