crypto: testmgr - mark ghash as fips_allowed

A self-test failure in fips mode means a panic. Well, gcm(aes)
self-tests currently fail in fips mode, as gcm is dependent on ghash,
which semi-recently got self-test vectors added, but wasn't marked as a
fips_allowed algorithm. Because of gcm's dependence on what is now seen
as a non-fips_allowed algorithm, its self-tests refuse to run.
Previously, ghash got a pass in fips mode, due to the lack of any test
vectors at all, and thus gcm self-tests were able to run. After this
patch, a 'modprobe tcrypt mode=35' no longer panics in fips mode, and
successful self-test of gcm(aes) is reported.

Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>