HW Relnotes: Remove traces of ar(4)

Remove two lost lines from the hardware release notes template, and the
past two major versions. They appeared in the original 4.4R/i386 notes
and were forgotten when the rest of the entry was removed was removed in
FreeBSD 8.0R.

Discussed with: emaste
Reviewed by: mhorne
Approved by: mhorne (mentor)
Differential Revision: https://reviews.freebsd.org/D50527