commit38b1f0fb42upstream. The wakeup mechanism via RTSDEN bit relies on the system using the RTS/CTS lines, so only allow such wakeup method when the system actually has RTS/CTS support. Fixes:bc85734b12("serial: imx: allow waking up on RTSD") Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com> Reviewed-by: Martin Kaiser <martin@kaiser.cx> Acked-by: Fugang Duan <fugang.duan@nxp.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>