PCI: frv: replace now removed pci_bus_b() causing build failure

In commit 94e6a9b93064 ("PCI: Remove pci_bus_b() and use
list_for_each_entry() directly") the function pci_bus_b() was removed, but
one instance of its usage was missed.

Replace it in the same fashion that the original commit did.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Yijing Wang <wangyijing@huawei.com>

arch/frv/mb93090-mb00/pci-frv.c

@@ -88,7 +88,7 @@ static void __init pcibios_allocate_bus_resources(struct list_head *bus_list)
 
 	/* Depth-First Search on bus tree */
 	for (ln=bus_list->next; ln != bus_list; ln=ln->next) {
-		bus = pci_bus_b(ln);
+		bus = list_entry(ln, struct pci_bus, node);
 		if ((dev = bus->self)) {
 			for (idx = PCI_BRIDGE_RESOURCES; idx < PCI_NUM_RESOURCES; idx++) {
 				r = &dev->resource[idx];