disp: msm: sde: Get connector roi state even PU disabled

Partial update will be disabled while panel operating
mode switch from command to video.
Display validation will be failed once CRTC and connector
ROI state are not the same.
So add this change to get connector roi state even partial
update is disabled.

Change-Id: Iebb1d001c1c11b659141ce301400704c16390ee6
Signed-off-by: Lei Chen <chenlei@codeaurora.org>