There's another place where nvramtool can look for

There's another place where nvramtool can look for
the CMOS checksum specification.
When using nvramtool on files (instead of CMOS and runtime firmware)
it's the only place.

Signed-off-by: Patrick Georgi <patrick.georgi@secunet.com>
Acked-by: Stefan Reinauer <stepan@coreboot.org>
git-svn-id: svn://svn.coreboot.org/coreboot/trunk@6282 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1