MF11 361044,361048: Deprecate ubsec(4) for FreeBSD 13.0.

With the removal of in-tree consumers of DES, Triple DES, and
MD5-HMAC, the only algorithm this driver still supports is SHA1-HMAC.
This is not very useful as a standalone algorithm (IPsec AH-only with
SHA1 would be the only user).

This driver has also not been kept up to date with the original driver
in OpenBSD which supports a few more cards and AES-CBC on newer cards.
The newest card currently supported by this driver was released in

Approved by: re (gjb)
Relnotes: yes