texture: Fix the async loop ceiling

The comment says that we're going to load textures in a loop until we
still have work to do, or if one iteration took more than 5
milliseconds, to avoid blowing up our frame budget, but the check is for
5 seconds, which is hardly a sensible value.

clutter/clutter-texture.c

@@ -1832,7 +1832,7 @@ texture_repaint_upload_func (gpointer user_data)
           clutter_texture_async_data_free (async_data);
         }
       while (upload_list != NULL &&
-             g_get_monotonic_time () < start_time + 5 * 1000000L);
+             g_get_monotonic_time () < start_time + 5 * 1000L);
     }
 
   if (upload_list != NULL)