drm/amd/display: add new windowed mpo odm minimal transition sequence

[why]
We do not have a programming sequence to support seamless transition
between MPC combine to ODM combine when plane count remains the same.
This can happen with windowed MPO ODM use cases when plane scaling
is changed over ODM Combine's capability.

[How]
We are adding a programming sequence specifically to handle the transition
between MPC combine and ODM combine during plane scaling change.
Reviewed-by: Aric Cyr <aric.cyr@amd.com>
Acked-by: Wayne Lin <wayne.lin@amd.com>
Signed-off-by: Wenjing Liu <wenjing.liu@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/inc/core_types.h

@@ -563,6 +563,17 @@ struct dc_state {
 	struct {
 		unsigned int stutter_period_us;
 	} perf_params;
+
+	struct {
+		/* used to temporarily backup plane states of a stream during
+		 * dc update. The reason is that plane states are overwritten
+		 * with surface updates in dc update. Once they are overwritten
+		 * current state is no longer valid. We want to temporarily
+		 * store current value in plane states so we can still recover
+		 * a valid current state during dc update.
+		 */
+		struct dc_plane_state plane_states[MAX_SURFACE_NUM];
+	} scratch;
 };
 
 struct replay_context {