USB: mos7720: fix hardware flow control

The register access to enable hardware flow control depends on the
device port number and not the port minor number.

Cc: stable@vger.kernel.org
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/serial/mos7720.c

@@ -1629,7 +1629,7 @@ static void change_port_settings(struct tty_struct *tty,
 		mos7720_port->shadowMCR |= (UART_MCR_XONANY);
 		/* To set hardware flow control to the specified *
 		 * serial port, in SP1/2_CONTROL_REG             */
-		if (port->number)
+		if (port_number)
 			write_mos_reg(serial, dummy, SP_CONTROL_REG, 0x01);
 		else
 			write_mos_reg(serial, dummy, SP_CONTROL_REG, 0x02);