Add missing __exit annotations to module exit func tun_cleanup().
Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Link: https://lore.kernel.org/r/20230814083000.3893589-1-william.xuanziyang@huawei.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>