Revert "disp: msm: sde: add secure session flag in sde_crtc state"

This reverts commit 184653cc.
The original fix was resulting in atomic check failures
while transitioning from secure UI in video mode.

Change-Id: If4da144e0582f8f59d0bf05b52602b1a5f5514c4
Signed-off-by: Yashwanth <yvulapu@codeaurora.org>