acpiphp: fix use of list_for_each macro

This patch fixes invalid usage of list_for_each()

list_for_each (node, &bridge_list) {
	bridge = (struct acpiphp_bridge *)node;
	...
}

This code works while the member of list node is located at the
head of struct acpiphp_bridge.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/pci/hotplug/acpiphp_glue.c

@@ -1693,14 +1693,10 @@ void __exit acpiphp_glue_exit(void)
  */
 int __init acpiphp_get_num_slots(void)
 {
-	struct list_head *node;
 	struct acpiphp_bridge *bridge;
-	int num_slots;
-
-	num_slots = 0;
+	int num_slots = 0;
 
-	list_for_each (node, &bridge_list) {
-		bridge = (struct acpiphp_bridge *)node;
+	list_for_each_entry (bridge, &bridge_list, list) {
 		dbg("Bus %04x:%02x has %d slot%s\n",
 				pci_domain_nr(bridge->pci_bus),
 				bridge->pci_bus->number, bridge->nr_slots,