PCI: replace struct pci_bus secondary/subordinate with busn_res

Replace the struct pci_bus secondary/subordinate members with the
struct resource busn_res.  Later we'll build a resource tree of these
bus numbers.

[bhelgaas: changelog]
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
diff --git a/arch/xtensa/kernel/pci.c b/arch/xtensa/kernel/pci.c
index eb30e35..9c57c1e 100644
--- a/arch/xtensa/kernel/pci.c
+++ b/arch/xtensa/kernel/pci.c
@@ -187,7 +187,7 @@
 		bus = pci_scan_root_bus(NULL, pci_ctrl->first_busno,
 					pci_ctrl->ops, pci_ctrl, &resources);
 		pci_ctrl->bus = bus;
-		pci_ctrl->last_busno = bus->subordinate;
+		pci_ctrl->last_busno = bus->busn_res.end;
 		if (next_busno <= pci_ctrl->last_busno)
 			next_busno = pci_ctrl->last_busno+1;
 	}