SE HMIBSC board debug console requires RS232 flow control, so enable corresponding support if RS232 gpios are present. Reviewed-by: Caleb Connolly <caleb.connolly@linaro.org> Signed-off-by: Sumit Garg <sumit.garg@linaro.org> Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org>