yabel: Use IS_ENABLED where appropriate

Change-Id: Ib078b21ddf0493ad6795c6ab79125b3917ff7049
Signed-off-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Reviewed-on: http://review.coreboot.org/12115
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
2 files changed