serial: exar: Fix mapping of port I/O resources

pcim_iomap_table only returns the table of mapping, it does not perform
them. For that, we need to call pcim_iomap, but only if that mapping was
not done before.

Fixes: d0aeaa83 ("serial: exar: split out the exar code from 8250_pci")
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250_exar.c

@@ -72,6 +72,9 @@ static int default_setup(struct exar8250 *priv, struct pci_dev *pcidev,
 	const struct exar8250_board *board = priv->board;
 	unsigned int bar = 0;
 
+	if (!pcim_iomap_table(pcidev)[bar] && !pcim_iomap(pcidev, bar, 0))
+		return -ENOMEM;
+
 	port->port.iotype = UPIO_MEM;
 	port->port.mapbase = pci_resource_start(pcidev, bar) + offset;
 	port->port.membase = pcim_iomap_table(pcidev)[bar] + offset;