drm/msm/sde: Add AD mode switch for IPC support

AD feature needs to switch to manual strength mode for two
frames when device exits the idle power collapse mode, and then
switch back to auto strength mode after 2 frames. This change
adds this support in the DRM based driver implementation.

Change-Id: I31c3a0337df2d370eddec75c68af24bb458db827
Signed-off-by: Ping Li <pingli@codeaurora.org>