drm/msm/sde: fix invalid connector state in crtc check

Connector state in crtc_atomic_check is still the old state, use
connector_mask to update the actual connector in the list to fix
zero connector issue.

Change-Id: I91541063acbb19beced3004a030c7f27abf9ee50
Signed-off-by: Xiaowen Wu <wxiaowen@codeaurora.org>