Crypto test failures in FIPS mode cause an immediate panic, but
on some system the cryptographic boundary extends beyond just
the Linux controlled domain.

Add a simple atomic notification chain to allow interested parties
to register to receive notification prior to us kicking the bucket.
Signed-off-by: NGilad Ben-Yossef <gilad@benyossef.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>