libpayload: Use #ifdef for CONFIG_* checks

Libpayload uses the linux kernel's config style, where CONFIG_* defines
don't get written for unset tristates.

Change-Id: I3f832cf86bca9a1e153d96af4bf6434a19eba2f6
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: http://review.coreboot.org/1847
Tested-by: build bot (Jenkins)
Reviewed-by: Anton Kochkov <anton.kochkov@gmail.com>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
4 files changed