config.h is a dependency so add it. Change-Id: Iac87039dd43aa75d49766b9a239fbd841ca6850c Signed-off-by: Arthur Heymans <arthur@aheymans.xyz> Reviewed-on: https://review.coreboot.org/c/coreboot/+/68244 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Paul Menzel <paulepanter@mailbox.org> Reviewed-by: Angel Pons <th3fanbus@gmail.com>