[POWERPC] Add "parent" struct device for PCI host bridges

Add a "parent" struct device to our PCI host bridge data structure so that
PCI can be rooted off another device in sysfs.

Note that arch/ppc doesn't use it, only arch/powerpc, though it's available
for both 32 and 64 bits.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

arch/powerpc/kernel/pci_32.c

@@ -1269,7 +1269,10 @@ pcibios_init(void)
 		if (pci_assign_all_buses)
 			hose->first_busno = next_busno;
 		hose->last_busno = 0xff;
-		bus = pci_scan_bus(hose->first_busno, hose->ops, hose);
+		bus = pci_scan_bus_parented(hose->parent, hose->first_busno,
+					    hose->ops, hose);
+		if (bus)
+			pci_bus_add_devices(bus);
 		hose->last_busno = bus->subordinate;
 		if (pci_assign_all_buses || next_busno <= hose->last_busno)
 			next_busno = hose->last_busno + pcibios_assign_bus_offset;

arch/powerpc/kernel/pci_64.c

@@ -513,7 +513,7 @@ void __devinit scan_phb(struct pci_controller *hose)
 
 	DBG("Scanning PHB %s\n", node ? node->full_name : "<NO NAME>");
 
-	bus = pci_create_bus(NULL, hose->first_busno, hose->ops, node);
+	bus = pci_create_bus(hose->parent, hose->first_busno, hose->ops, node);
 	if (bus == NULL) {
 		printk(KERN_ERR "Failed to create bus for PCI domain %04x\n",
 		       hose->global_number);

include/asm-powerpc/pci-bridge.h

@@ -25,6 +25,7 @@ struct pci_controller {
 	int node;
 	void *arch_data;
 	struct list_head list_node;
+	struct device *parent;
 
 	int first_busno;
 	int last_busno;

include/asm-ppc/pci-bridge.h

@@ -43,6 +43,7 @@ struct pci_controller {
 	struct pci_controller *next;
         struct pci_bus *bus;
 	void *arch_data;
+	struct device *parent;
 
 	int first_busno;
 	int last_busno;