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
2005.

Reviewed by:	cem
MFC after:	1 week
Relnotes:	yes
Sponsored by:	Chelsio Communications
Differential Revision:	https://reviews.freebsd.org/D24691

share/man/man4/ubsec.4

@@ -48,6 +48,15 @@ module at boot time, place the following line in
 .Bd -literal -offset indent
 ubsec_load="YES"
 .Ed
+.Sh DEPRECATION NOTICE
+The
+.Nm
+driver is not present in
+.Fx 13.0
+and later.
+The majority of crypto algorithms supported by this driver are no longer
+used by the kernel in
+.Fx 13.0 .
 .Sh DESCRIPTION
 The
 .Nm

sys/dev/ubsec/ubsec.c

@@ -472,6 +472,7 @@ ubsec_attach(device_t dev)
 		crypto_kregister(sc->sc_cid, CRK_MOD_EXP_CRT, 0);
 #endif
 	}
+	gone_in_dev(dev, 13, "Does not support modern crypto algorithms");
 	return (0);
 bad4:
 	while (!SIMPLEQ_EMPTY(&sc->sc_freequeue)) {