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: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 55ec44a..23362e8 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -287,7 +287,7 @@
 	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) {