drm: Remove redundant NULL check during atomic plane commit

plane_state can't be NULL anywhere in this function, so the NULL check
at the end is redundant, remove it.

Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1493214013-15580-9-git-send-email-imre.deak@intel.comReviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

drivers/gpu/drm/drm_plane_helper.c

@@ -511,12 +511,10 @@ int drm_plane_helper_commit(struct drm_plane *plane,
 	if (plane_funcs->cleanup_fb)
 		plane_funcs->cleanup_fb(plane, plane_state);
 out:
-	if (plane_state) {
 	if (plane->funcs->atomic_destroy_state)
 		plane->funcs->atomic_destroy_state(plane, plane_state);
 	else
 		drm_atomic_helper_plane_destroy_state(plane, plane_state);
-	}
 
 	return ret;
 }