backport: remove stddef.h inclusions

The verification code was copied from userspace code which includes
stddef.h.  In the kernel, this header should not be included, so
remove those cases.

Fixes: 988e2af4b7a0 ("backports: add signature verification code")
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
3 files changed