sockstat: microoptimize cap-getnameinfo

Revert a change to the cap_getnameinfo, accidentally introduced in
0726c6574f8, that caused cap_getnameinfo to populate a buffer which was
about to be thrown away.

Fixes: 0726c6574f889507e5030173bf4c82c80911394d
Sponsored by: ConnectWise
Reviewed by: Damin Rido <rido@FreeBSD.org>
Pull Request: https://github.com/freebsd/freebsd-src/pull/1753