Introduce an architecture sorting of boards. This is to allow for
easier maintenance going forward as the number of boards grows. It
will be easier for any scripts to know the board/arch mapping without
having to maintain an explicit list of what boards are associated with
which arch. We can also do things like have architecture maintainers
cover reviews and branches for arch/${ARCH} and boards/${ARCH} going
forward.
Change-Id: I02e0a30292b31fad58fb5dfab2682ad1c5a7d5a7
Signed-off-by: Kumar Gala <kumar.gala@linaro.org>