Add dev firmware key to devkeys.

The existing keys are kept the same, so that old dev kernels and
firmware remain compatible with new kernels and firmware.

Change-Id: I4177d1868904a477d79b9f2e6de88ed756ed57b4

BUG=chrome-os-partner:2218
TEST=manual:

Build firmware with new keys.

Boot with dev switch on.
Run 'crossystem mainfw_act mainfw_type'.
Should see "A developer"

Boot with dev switch off.
Run 'crossystem mainfw_act mainfw_type'.
Should see "B normal"

Review URL: http://codereview.chromium.org/6580035
4 files changed