`stddef.h` should only provide the definitions defined by ISO or Posix.
The included `commonlib/bsd/helpers.h` provide a lot of non standard
definitions that may interfere with definitions from the application.
Change-Id: Ia71edbc3ffe6694ff4b971decf3a41f915264bc8
Signed-off-by: Thomas Heijligen <src@posteo.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/70116
Reviewed-by: Elyes Haouas <ehaouas@noos.fr>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>