Sometimes new boards have not been tested with official docker so let's add
instructions to do it with utils/docker-run.
Cc: Luca Ceresoli <luca@lucaceresoli.net>
Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>
Reviewed-by: Luca Ceresoli <luca@lucaceresoli.net>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>