Add FreeBSD/ARM notes.

These do not have corresponding revision numbers, since
the updates took place over a large span of revisions,
not one revision in particular.

Submitted/prepared by:	ian
Sponsored by:	The FreeBSD Foundation
Fix typo.

Submitted by:	Hugo Lombard <hal@elizium.za.net>
Use <acronym> and <literal> in a few places where needed.
Minor rewording to r264732 entry.

Sponsored by:	The FreeBSD Foundation
We do not differentiate the SMP from GENERIC kernel anymore,
so remove mention of it.

Sponsored by:	The FreeBSD Foundation
Minor rewording to a few sections.

Sponsored by:	The FreeBSD Foundation