powerpc/pci: Fix PCI<->OF matching of old style multifunc devices

Old OF variants used to create a 'dummy' parent node "multifunc-device"
for devices with more than one PCI function. Our code that matches OF
nodes to PCI devices dealt with that in one place but not in another,
this fixes it.

This has the practical effect of fixing interrupt routing of multifunction
PCI cards on some older PowerMac machines.
Signed-off-by: Tom Arbuckle <tom.d.arbuckle@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/kernel/pci_32.c

@@ -218,16 +218,23 @@ scan_OF_pci_childs(struct device_node *parent, pci_OF_scan_iterator filter, void
 static struct device_node *scan_OF_for_pci_dev(struct device_node *parent,
 					       unsigned int devfn)
 {
-	struct device_node *np;
+	struct device_node *np, *cnp;
 	const u32 *reg;
 	unsigned int psize;
 
 	for_each_child_of_node(parent, np) {
 		reg = of_get_property(np, "reg", &psize);
-		if (reg == NULL || psize < 4)
-			continue;
-		if (((reg[0] >> 8) & 0xff) == devfn)
+                if (reg && psize >= 4 && ((reg[0] >> 8) & 0xff) == devfn)
 			return np;
+
+		/* Note: some OFs create a parent node "multifunc-device" as
+		 * a fake root for all functions of a multi-function device,
+		 * we go down them as well. */
+                if (!strcmp(np->name, "multifunc-device")) {
+                        cnp = scan_OF_for_pci_dev(np, devfn);
+                        if (cnp)
+                                return cnp;
+                }
 	}
 	return NULL;
 }