drm/amd/display: Change optimized_required logic

Rather than setting it every time there's a full update with surface
count > 0, set it when we need to do plane_atomic_disconnect. Also make
sure that we unset the flag in plane_atomic_disable, so that in the
event we run through a sequence where we do disconnect followed by an
immediate disable, we do not do unnecessarily request a passive flip to
do the optimization.

Signed-off-by: Andrew Jiang <Andrew.Jiang@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>