ACPI/button: convert to module_acpi_driver()

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/button.c

@@ -450,15 +450,4 @@ static int acpi_button_remove(struct acpi_device *device, int type)
 	return 0;
 }
 
-static int __init acpi_button_init(void)
-{
-	return acpi_bus_register_driver(&acpi_button_driver);
-}
-
-static void __exit acpi_button_exit(void)
-{
-	acpi_bus_unregister_driver(&acpi_button_driver);
-}
-
-module_init(acpi_button_init);
-module_exit(acpi_button_exit);
+module_acpi_driver(acpi_button_driver);