NFS: nfs_encode_fh: Remove S_AUTOMOUNT check

Now with NFSD being able to cross into auto mounts,
the check can be removed.

Signed-off-by: Richard Weinberger <richard@nod.at>
Reviewed-by: Ian Kent <raven@themaw.net>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Acked-by: Anna Schumaker <Anna.Schumaker@Netapp.com>