PCI: generic: Pass starting bus number to pci_scan_root_bus()

If the bus is being configured with a bus-range that does not start at
zero, pass that starting bus number to pci_scan_root_bus().  Passing the
incorrect value of zero causes attempted config accesses outside of the
supported range, which cascades to an OOPs spew and eventual kernel panic.
Signed-off-by: David Daney <david.daney@cavium.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Will Deacon <will.deacon@arm.com>

drivers/pci/host/pci-host-generic.c

@@ -251,7 +251,8 @@ static int gen_pci_probe(struct platform_device *pdev)
 	if (!pci_has_flag(PCI_PROBE_ONLY))
 		pci_add_flags(PCI_REASSIGN_ALL_RSRC | PCI_REASSIGN_ALL_BUS);
 
-	bus = pci_scan_root_bus(dev, 0,
+
+	bus = pci_scan_root_bus(dev, pci->cfg.bus_range->start,
 				&pci->cfg.ops->ops, pci, &pci->resources);
 	if (!bus) {
 		dev_err(dev, "Scanning rootbus failed");