mm/secretmem: add __init annotation to secretmem_init()

It's a fs_initcall entry, add __init annotation to it.

Link: https://lkml.kernel.org/r/20220915011602.176967-1-xiujianfeng@huawei.comSigned-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Cc: Mike Rapoport <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/secretmem.c

@@ -276,7 +276,7 @@ static struct file_system_type secretmem_fs = {
 	.kill_sb	= kill_anon_super,
 };
 
-static int secretmem_init(void)
+static int __init secretmem_init(void)
 {
 	int ret = 0;