Revert "ubifs: ubifs_symlink: Fix memleak of inode->i_link in error path"

This reverts commit 6379b44c. Commit
1e022216 ("ubifs: ubifs_symlink: Fix memleak of inode->i_link in
error path") is applied again in commit 6379b44c

 ("ubifs:
ubifs_symlink: Fix memleak of inode->i_link in error path"), which
changed ubifs_mknod (It won't become a real problem). Just revert it.

Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>