cbfstool: fix --machine

The help text says --machine, but the code
actually checked for --arch. Fix it!

Change-Id: Ib9bbf758b82ef070550348e897419513495f154b
Signed-off-by: Stefan Reinauer <reinauer@google.com>
Reviewed-on: http://review.coreboot.org/3009
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
1 file changed