FCP-100: armv7 plan

[Warner Losh]

Greetings,

This will serve as 'Last Call' for any objections to the plan to create an
armv7 MACHINE_ARCH in FreeBSD, as documented in FCP-0100.

Please see https://github.com/freebsd/fcp/blob/master/fcp-0100.md for all
the details. This has been discussed in the mailing lists, on IRC, etc and
I believe that I've captured the consensus from those discussions.

I'm interested in any last minute comments, but as far as I can tell I have
consensus on this issue. Absent any comments to the contrary, I'll proceed
to having core@ vote that this document represents consensus. Now is the
time to speak up if I've gotten anything wrong.

Once the core vote is done, I plan on committing the code reviews I have
open on this:
https://reviews.freebsd.org/D12027
and
https://reviews.freebsd.org/D12010
(again, I welcome any commits / criticisms in phabricator on the specific
issues in this code)

Thanks for any comments...

Warner