drm/amd/display: Reduce stack size

Reduce stack size pointed by clang:

amdgpu_dm/amdgpu_dm.c:8655:13: error: stack frame size (1048) exceeds limit (1024) in 'amdgpu_dm_atomic_commit_tail' [-Werror,-Wframe-larger-than]
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Acked-by: Alan Liu <haoping.liu@amd.com>
Signed-off-by: Rodrigo Siqueira <rodrigo.siqueira@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -8710,13 +8710,12 @@ static void amdgpu_dm_atomic_commit_tail(struct drm_atomic_state *state)
 		struct dm_connector_state *dm_new_con_state = to_dm_connector_state(new_con_state);
 		struct dm_connector_state *dm_old_con_state = to_dm_connector_state(old_con_state);
 		struct amdgpu_crtc *acrtc = to_amdgpu_crtc(dm_new_con_state->base.crtc);
-		struct dc_surface_update dummy_updates[MAX_SURFACES];
+		struct dc_surface_update *dummy_updates;
 		struct dc_stream_update stream_update;
 		struct dc_info_packet hdr_packet;
 		struct dc_stream_status *status = NULL;
 		bool abm_changed, hdr_changed, scaling_changed;
 
-		memset(&dummy_updates, 0, sizeof(dummy_updates));
 		memset(&stream_update, 0, sizeof(stream_update));
 
 		if (acrtc) {
@@ -8775,6 +8774,7 @@ static void amdgpu_dm_atomic_commit_tail(struct drm_atomic_state *state)
 		 * Here we create an empty update on each plane.
 		 * To fix this, DC should permit updating only stream properties.
 		 */
+		dummy_updates = kzalloc(sizeof(struct dc_surface_update) * MAX_SURFACES, GFP_ATOMIC);
 		for (j = 0; j < status->plane_count; j++)
 			dummy_updates[j].surface = status->plane_states[0];
 
@@ -8786,6 +8786,7 @@ static void amdgpu_dm_atomic_commit_tail(struct drm_atomic_state *state)
 					    dm_new_crtc_state->stream,
 					    &stream_update);
 		mutex_unlock(&dm->dc_lock);
+		kfree(dummy_updates);
 	}
 
 	/**