drm/amd/display: Update ABM crtc state on non-modeset

[Why]
Somewhere in the atomic check reshuffle ABM got lost.
ABM is a crtc property (copied from a connector property).
It can change without a modeset, just like underscan.

[How]
In the skip_modeset branch of atomic check crtc updates,
copy over the abm property.
Signed-off-by: David Francis <David.Francis@amd.com>
Reviewed-by: Nicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -5689,6 +5689,9 @@ static int dm_update_crtc_state(struct amdgpu_display_manager *dm,
 		update_stream_scaling_settings(
 			&new_crtc_state->mode, dm_new_conn_state, dm_new_crtc_state->stream);
 
+	/* ABM settings */
+	dm_new_crtc_state->abm_level = dm_new_conn_state->abm_level;
+
 	/*
 	 * Color management settings. We also update color properties
 	 * when a modeset is needed, to ensure it gets reprogrammed.