cbfstool: add a constant for the aarch64

Change-Id: Ide2c8b778447de66d95bd8c55b378aa2051ac2a0
Signed-off-by: Ronald G. Minnich <rminnich@google.com>
Reviewed-on: http://review.coreboot.org/4091
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@google.com>
1 file changed