s390/pci: improve bar check

Improve the bar check in pci_iomap_range to cover functions
for which we recognize more bars than what we can access due
to AR restrictions.
Signed-off-by: Sebastian Ott <sebott@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/pci/pci.c

@@ -285,7 +285,7 @@ void __iomem *pci_iomap_range(struct pci_dev *pdev,
 	struct zpci_dev *zdev =	to_zpci(pdev);
 	int idx;
 
-	if (!pci_resource_len(pdev, bar))
+	if (!pci_resource_len(pdev, bar) || bar >= PCI_BAR_COUNT)
 		return NULL;
 
 	idx = zdev->bars[bar].map_idx;