nilfs2: fix memory leak in nilfs_sysfs_delete_snapshot_group

kobject_put() should be used to cleanup the memory associated with the
kobject instead of kobject_del().  See the section "Kobject removal" of
"Documentation/core-api/kobject.rst".

Link: https://lkml.kernel.org/r/20210629022556.3985106-7-sunnanyong@huawei.com
Link: https://lkml.kernel.org/r/1625651306-10829-7-git-send-email-konishi.ryusuke@gmail.comSigned-off-by: Nanyong Sun <sunnanyong@huawei.com>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/nilfs2/sysfs.c

@@ -202,7 +202,7 @@ int nilfs_sysfs_create_snapshot_group(struct nilfs_root *root)
 
 void nilfs_sysfs_delete_snapshot_group(struct nilfs_root *root)
 {
-	kobject_del(&root->snapshot_kobj);
+	kobject_put(&root->snapshot_kobj);
 }
 
 /************************************************************************