powerpc/pci: Clean up direct access to sysdata by 4xx platforms

We shouldn't directly access sysdata to get the pci_controller.  Instead
use pci_bus_to_host() for this purpose.  In the future we might have
sysdata be a device_node to match ppc64 and unify the code between ppc32
& ppc64.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/sysdev/ppc4xx_pci.c

@@ -1295,7 +1295,7 @@ static void __iomem *ppc4xx_pciex_get_config_base(struct ppc4xx_pciex_port *port
 static int ppc4xx_pciex_read_config(struct pci_bus *bus, unsigned int devfn,
 				    int offset, int len, u32 *val)
 {
-	struct pci_controller *hose = (struct pci_controller *) bus->sysdata;
+	struct pci_controller *hose = pci_bus_to_host(bus);
 	struct ppc4xx_pciex_port *port =
 		&ppc4xx_pciex_ports[hose->indirect_type];
 	void __iomem *addr;
@@ -1352,7 +1352,7 @@ static int ppc4xx_pciex_read_config(struct pci_bus *bus, unsigned int devfn,
 static int ppc4xx_pciex_write_config(struct pci_bus *bus, unsigned int devfn,
 				     int offset, int len, u32 val)
 {
-	struct pci_controller *hose = (struct pci_controller *) bus->sysdata;
+	struct pci_controller *hose = pci_bus_to_host(bus);
 	struct ppc4xx_pciex_port *port =
 		&ppc4xx_pciex_ports[hose->indirect_type];
 	void __iomem *addr;