tty/8250 Add check for pci_ioremap_bar failure

Add check for pci_ioremap_bar failure
Signed-off-by: NMatt Schulte <matts@commtech-fastcom.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250_pci.c

@@ -1172,6 +1172,8 @@ pci_xr17v35x_setup(struct serial_private *priv,
 	u8 __iomem *p;
 
 	p = pci_ioremap_bar(priv->dev, 0);
+	if (p == NULL)
+		return -ENOMEM;
 
 	port->port.flags |= UPF_EXAR_EFR;