flashrom uses cmocka for unit testing. Install it so that the CI can use it. Change-Id: I5c168e480d6f4cbfbbd175ecb035c88bfcbac00b Signed-off-by: Felix Singer <felixsinger@posteo.net> Reviewed-on: https://review.coreboot.org/c/coreboot/+/67272 Reviewed-by: Angel Pons <th3fanbus@gmail.com> Tested-by: build bot (Jenkins) <no-reply@coreboot.org>