serial: imx: fix polarity of RI

When in DTE mode, the bit USR2_RIIN is active low. So invert the logic
accordingly.

Fixes: 90ebc483 ("serial: imx: repair and complete handshaking")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/imx.c

@@ -800,9 +800,9 @@ static unsigned int imx_get_hwmctrl(struct imx_port *sport)
 	if (!(usr1 & USR2_DCDIN))
 		tmp |= TIOCM_CAR;
 
-	/* in DCE mode RIIN is always 0 */
-	if (readl(sport->port.membase + USR2) & USR2_RIIN)
-		tmp |= TIOCM_RI;
+	if (sport->dte_mode)
+		if (!(readl(sport->port.membase + USR2) & USR2_RIIN))
+			tmp |= TIOCM_RI;
 
 	return tmp;
 }