ufs: Fix warning from unlock_new_inode()

Commit e4502c63 (ufs: deal with nfsd/iget races) introduced
unlock_new_inode() call into ufs_add_nondir(). However that function
gets called also from ufs_link() which hands it already initialized
inode and thus unlock_new_inode() complains. The problem is harmless but
annoying.

Fix the problem by opencoding necessary stuff in ufs_link()

Fixes: e4502c63
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>