PCI: sparse warning (trivial)

Assigning zero where NULL should be used.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
index 628ea20..42eea5fb 100644
--- a/drivers/pci/bus.c
+++ b/drivers/pci/bus.c
@@ -56,7 +56,7 @@
 	int i;
 
 	for (i = 0; i < PCI_BRIDGE_RESOURCE_NUM; i++)
-		bus->resource[i] = 0;
+		bus->resource[i] = NULL;
 
 	list_for_each_entry_safe(bus_res, tmp, &bus->resources, list) {
 		list_del(&bus_res->list);