powerpc/pci: Clean up direct access to sysdata by powermac platforms

We shouldn't directly access sysdata to get the device node but call
pci_bus_to_OF_node() for this purpose.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/platforms/powermac/setup.c

@@ -655,7 +655,7 @@ static int __init pmac_probe(void)
 /* Move that to pci.c */
 static int pmac_pci_probe_mode(struct pci_bus *bus)
 {
-	struct device_node *node = bus->sysdata;
+	struct device_node *node = pci_bus_to_OF_node(bus);
 
 	/* We need to use normal PCI probing for the AGP bus,
 	 * since the device for the AGP bridge isn't in the tree.