NFSD: drop support for ancient filehandles

[ Upstream commit c645a883 ]

Filehandles not in the "new" or "version 1" format have not been handed
out for new mounts since Linux 2.4 which was released 20 years ago.
I think it is safe to say that no such file handles are still in use,
and that we can drop support for them.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>