isdn: i4l: Remove ASYNC_CTS_FLOW

ISDN4Linux always enables CTS flow control and does not use the
tty_port_cts_enabled() helper function; remove ASYNC_CTS_FLOW
state enable/disable.

cc: Karsten Keil <isdn@linux-pingi.de>
cc: <netdev@vger.kernel.org>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/isdn/i4l/isdn_tty.c

@@ -1043,11 +1043,6 @@ isdn_tty_change_speed(modem_info *info)
 	if (!(cflag & PARODD))
 		cval |= UART_LCR_EPAR;
 
-	/* CTS flow control flag and modem status interrupts */
-	if (cflag & CRTSCTS) {
-		port->flags |= ASYNC_CTS_FLOW;
-	} else
-		port->flags &= ~ASYNC_CTS_FLOW;
 	if (cflag & CLOCAL)
 		port->flags &= ~ASYNC_CHECK_CD;
 	else {