Updates to the x86 assembly language chapter.

This is a very unusual piece of documentation in that it is maintained
by an outside author who thinks he has a better home-grown
documentation management system than ours, so he now supports
DocBook/SGML as an "output" format to his own system. His output is
perfectly valid DocBook but the indentation is mostly non-existent,
and 'tidy -xml' breaks things.

Anyway, please send updates to this chapter directly to the submitter.

Submitted by: G. Adam Stanislav (adam@whizkidtech.net)
Discussed on: freebsd-doc