Add scripts to increment single fm/kernel keys.

For firmware and kernel key increment testing we need to be able to
rev only particular keys and verify an autoupdate works.

BUG=None
TEST=Ran it
BRANCH=None

Change-Id: Ic814480b4bf8fbc994132fcd7ba519c3be9b0ccd
Reviewed-on: https://gerrit.chromium.org/gerrit/32458
Reviewed-by: Mike Frysinger <[email protected]>
Commit-Ready: Kris Rambish <[email protected]>
Tested-by: Kris Rambish <[email protected]>
5 files changed