PCI: release busn_res when removing bus

Release bus number resource when removing a bus.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
diff --git a/drivers/pci/remove.c b/drivers/pci/remove.c
index fd77e2b..04a4861 100644
--- a/drivers/pci/remove.c
+++ b/drivers/pci/remove.c
@@ -68,6 +68,7 @@
 
 	down_write(&pci_bus_sem);
 	list_del(&pci_bus->node);
+	pci_bus_release_busn_res(pci_bus);
 	up_write(&pci_bus_sem);
 	if (!pci_bus->is_added)
 		return;