Define pcibus_to_node() for IP27.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/pci/pci-ip27.c b/arch/mips/pci/pci-ip27.c
index 068e0e5..efc96ce 100644
--- a/arch/mips/pci/pci-ip27.c
+++ b/arch/mips/pci/pci-ip27.c
@@ -485,5 +485,12 @@
 	pci_disable_swapping(d);
 }
 
+int pcibus_to_node(struct pci_bus *bus)
+{
+	struct bridge_controller *bc = BRIDGE_CONTROLLER(bus);
+
+	return bc->nasid;
+}
+
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_SGI, PCI_DEVICE_ID_SGI_IOC3,
 	pci_fixup_ioc3);