PCI: fix wrong assumption in pci_read_bridge_bases

Current pci_read_bridge_bases() has an assumption that pci_bus->self
is NULL on the pci root bus (It checks pci_bus->self to see if the pci
bus is root bus). But is might not true on some platforms. We must
check pci_bus->parent instead.
Signed-off-by: NKenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>

drivers/pci/probe.c

@@ -287,7 +287,7 @@ void __devinit pci_read_bridge_bases(struct pci_bus *child)
 	struct resource *res;
 	int i;
 
-	if (!dev)		/* It's a host bus, nothing to read */
+	if (!child->parent)	/* It's a host bus, nothing to read */
 		return;
 
 	if (dev->transparent) {