serial/imx: disable hardware flow control at startup

We only want to enable hardware flow control if RTS/CTS pins
are connected.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 147c9e1..8cdfbd3 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -761,6 +761,8 @@
 
 	temp = readl(sport->port.membase + UCR2);
 	temp |= (UCR2_RXEN | UCR2_TXEN);
+	if (!sport->have_rtscts)
+		temp |= UCR2_IRTS;
 	writel(temp, sport->port.membase + UCR2);
 
 	if (USE_IRDA(sport)) {