lib: memzero_explicit: add comment for its usage
lib: memzero_explicit: add comment for its usage

Lets improve the comment to add a note on when to use memzero_explicit()
for those not digging through the git logs. We don't want people to
pollute places with memzero_explicit() where it's not really necessary.

Reference: https://lkml.org/lkml/2015/1/4/190
Suggested-by: Herbert Xu <ef65de1c7be0aa837fe7b25ba9a7739905af6a55@gondor.apana.org.au>
Signed-off-by: Daniel Borkmann <9ff04a02a69f376b2b9aeec27187017cbf3cf5f9@redhat.com>
Signed-off-by: Herbert Xu <ef65de1c7be0aa837fe7b25ba9a7739905af6a55@gondor.apana.org.au>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs