Not all ports have retimers. Only register a retimer switch if the "retimer-switch" property is present for that port's mux device. Signed-off-by: Prashant Malani <pmalani@chromium.org> Reviewed-by: Benson Leung <bleung@chromium.org> Link: https://lore.kernel.org/r/20230104060846.112216-2-pmalani@chromium.org