drm/nouveau/kms/nv50: use the correct state for base channel notifier setup

Fixes: 857263 ("drm/nouveau: Handle drm_atomic_helper_swap_state failure")
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Tested-by: Lyude Paul <lyude@redhat.com>
Reviewed by: Lyude Paul <lyude@redhat.com>

drivers/gpu/drm/nouveau/nv50_display.c

@@ -4099,7 +4099,7 @@ nv50_disp_atomic_commit(struct drm_device *dev,
 {
 	struct nouveau_drm *drm = nouveau_drm(dev);
 	struct nv50_disp *disp = nv50_disp(dev);
-	struct drm_plane_state *old_plane_state;
+	struct drm_plane_state *new_plane_state;
 	struct drm_plane *plane;
 	struct drm_crtc *crtc;
 	bool active = false;
@@ -4129,8 +4129,8 @@ nv50_disp_atomic_commit(struct drm_device *dev,
 	if (ret)
 		goto err_cleanup;
 
-	for_each_old_plane_in_state(state, plane, old_plane_state, i) {
-		struct nv50_wndw_atom *asyw = nv50_wndw_atom(old_plane_state);
+	for_each_new_plane_in_state(state, plane, new_plane_state, i) {
+		struct nv50_wndw_atom *asyw = nv50_wndw_atom(new_plane_state);
 		struct nv50_wndw *wndw = nv50_wndw(plane);
 
 		if (asyw->set.image) {