drm/amd/display: Update scaling settings on modeset

[Why]
We update scaling settings when scaling mode has been changed.
However when changing mode from native resolution the scaling mode previously
set gets ignored.

[How]
Perform scaling settings update on modeset.

Signed-off-by: Roman Li <[e-mail]>
Reviewed-by: Nicholas Kazlauskas <[e-mail]>
Acked-by: Stylon Wang <[e-mail]>
Tested-by: Daniel Wheeler <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

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

···
 	BUG_ON(dm_new_crtc_state->stream == NULL);
 
 	/* Scaling or underscan settings */
-	if (is_scaling_state_different(dm_old_conn_state, dm_new_conn_state))
+	if (is_scaling_state_different(dm_old_conn_state, dm_new_conn_state) ||
+				drm_atomic_crtc_needs_modeset(new_crtc_state))
 		update_stream_scaling_settings(
 			&new_crtc_state->mode, dm_new_conn_state, dm_new_crtc_state->stream);