ACPI: Drop ACPI bus notifier call chain

There are no users of the ACPI bus notifier call chain,
acpi_bus_notify_list, any more, so drop it.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/bus.c

@@ -499,19 +499,6 @@ static void acpi_bus_check_scope(acpi_handle handle)
 	 */
 }
 
-static BLOCKING_NOTIFIER_HEAD(acpi_bus_notify_list);
-int register_acpi_bus_notifier(struct notifier_block *nb)
-{
-	return blocking_notifier_chain_register(&acpi_bus_notify_list, nb);
-}
-EXPORT_SYMBOL_GPL(register_acpi_bus_notifier);
-
-void unregister_acpi_bus_notifier(struct notifier_block *nb)
-{
-	blocking_notifier_chain_unregister(&acpi_bus_notify_list, nb);
-}
-EXPORT_SYMBOL_GPL(unregister_acpi_bus_notifier);
-
 /**
  * acpi_bus_notify
  * ---------------
@@ -525,9 +512,6 @@ static void acpi_bus_notify(acpi_handle handle, u32 type, void *data)
 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Notification %#02x to handle %p\n",
 			  type, handle));
 
-	blocking_notifier_call_chain(&acpi_bus_notify_list,
-		type, (void *)handle);
-
 	switch (type) {
 
 	case ACPI_NOTIFY_BUS_CHECK:

include/acpi/acpi_bus.h

@@ -366,8 +366,6 @@ extern int acpi_notifier_call_chain(struct acpi_device *, u32, u32);
 extern int register_acpi_notifier(struct notifier_block *);
 extern int unregister_acpi_notifier(struct notifier_block *);
 
-extern int register_acpi_bus_notifier(struct notifier_block *nb);
-extern void unregister_acpi_bus_notifier(struct notifier_block *nb);
 /*
  * External Functions
  */