kevin/gru: remove board almost completely

Kevin/Gru are running out of space and we already have another ARM board on
ToT for development. Remove maintenance burden of keeping them around.

BRANCH=none
BUG=chromium:851512
TEST=build_packages --board=kevin works with dependent CLs.
CQ-DEPEND=CL:1102565,CL:*640973,CL:*640974

Change-Id: Ie7c65c7799acc9f4d266e40b29b37240fec345c6
Signed-off-by: Jett Rink <jettrink@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1100011
Reviewed-by: Ilja H. Friedel <ihf@chromium.org>
Reviewed-by: Randall Spangler <rspangler@chromium.org>
14 files changed