serial: sh-sci: Fix could not remove dev_attr_rx_fifo_timeout

This patch fixes an issue that the sci_remove() could not remove
dev_attr_rx_fifo_timeout because uart_remove_one_port() set
the port->port.type to PORT_UNKNOWN.

Reported-by: Hiromitsu Yamasaki <hiromitsu.yamasaki.ym@renesas.com>
Fixes: 5d23188 ("serial: sh-sci: make RX FIFO parameters tunable via sysfs")
Cc: <stable@vger.kernel.org> # v4.11+
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Reviewed-by: Ulrich Hecht <uli+renesas@fpond.eu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: shimoday

drivers/tty/serial/sh-sci.c

@@ -3102,6 +3102,7 @@ static struct uart_driver sci_uart_driver = {
 static int sci_remove(struct platform_device *dev)
 {
 	struct sci_port *port = platform_get_drvdata(dev);
+	unsigned int type = port->port.type;	/* uart_remove_... clears it */
 
 	sci_ports_in_use &= ~BIT(port->port.line);
 	uart_remove_one_port(&sci_uart_driver, &port->port);
@@ -3112,8 +3113,7 @@ static int sci_remove(struct platform_device *dev)
 		sysfs_remove_file(&dev->dev.kobj,
 				  &dev_attr_rx_fifo_trigger.attr);
 	}
-	if (port->port.type == PORT_SCIFA || port->port.type == PORT_SCIFB ||
-	    port->port.type == PORT_HSCIF) {
+	if (type == PORT_SCIFA || type == PORT_SCIFB || type == PORT_HSCIF) {
 		sysfs_remove_file(&dev->dev.kobj,
 				  &dev_attr_rx_fifo_timeout.attr);
 	}