[POWERPC] Use dev_set_name in pci_64.c

During the next merge window, pci_name()'s return value will become
const, so use the new dev_set_name() instead to avoid the warning (from
linux-next):

arch/powerpc/kernel/pci_64.c: In function 'of_create_pci_dev':
arch/powerpc/kernel/pci_64.c:193: warning: passing argument 1 of 'sprintf' discards qualifiers from pointer target type

Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/kernel/pci_64.c

@@ -189,7 +189,7 @@ struct pci_dev *of_create_pci_dev(struct device_node *node,
 
 	dev->cfg_size = pci_cfg_space_size(dev);
 
-	sprintf(pci_name(dev), "%04x:%02x:%02x.%d", pci_domain_nr(bus),
+	dev_set_name(&dev->dev, "%04x:%02x:%02x.%d", pci_domain_nr(bus),
 		dev->bus->number, PCI_SLOT(devfn), PCI_FUNC(devfn));
 	dev->class = get_int_prop(node, "class-code", 0);
 	dev->revision = get_int_prop(node, "revision-id", 0);