drm/qxl: drop redundant code

Not needed, qxl_io_destroy_primary() does that for us.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: http://patchwork.freedesktop.org/patch/msgid/20210511104522.2694803-2-kraxel@redhat.com

drivers/gpu/drm/qxl/qxl_display.c

@@ -677,10 +677,8 @@ static void qxl_primary_atomic_disable(struct drm_plane *plane,
 
 		if (bo->shadow)
 			bo = bo->shadow;
-		if (bo->is_primary) {
+		if (bo->is_primary)
 			qxl_io_destroy_primary(qdev);
-			bo->is_primary = false;
-		}
 	}
 }