fix acpi build error

See: rockchip-linux/kernel#139

include/acpi/acpi_bus.h

@@ -384,6 +384,7 @@ struct acpi_data_node {
 	const char *name;
 	acpi_handle handle;
 	struct fwnode_handle fwnode;
+	struct fwnode_handle *parent;
 	struct acpi_device_data data;
 	struct list_head sibling;
 	struct kobject kobj;