f2fs: fix typo in comment of f2fs_do_add_link

stakable/stackable
Signed-off-by: Liu Song <fishland@aliyun.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/dir.c

@@ -779,7 +779,7 @@ int f2fs_do_add_link(struct inode *dir, const struct qstr *name,
 		return err;
 
 	/*
-	 * An immature stakable filesystem shows a race condition between lookup
+	 * An immature stackable filesystem shows a race condition between lookup
 	 * and create. If we have same task when doing lookup and create, it's
 	 * definitely fine as expected by VFS normally. Otherwise, let's just
 	 * verify on-disk dentry one more time, which guarantees filesystem