Add a script to generate a keypair for signing Staff RW firmware.

Staff decided to leverage the key format of Hammer therefore this
script calls Hammer's one to generate a key pair and renames them to
key_staff*.

BUG=b:66889892
TEST=Run this script in the chroot and verify the generated key pair.
BRANCH=None

Change-Id: I73162efaba47a8c08336805130ced0be25ab262a
Reviewed-on: https://chromium-review.googlesource.com/688522
Commit-Ready: Marco Chen <marcochen@chromium.org>
Tested-by: Marco Chen <marcochen@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
4 files changed