crypto: testmgr - disallow plain ghash in FIPS mode

ghash may be used only as part of the gcm(aes) construction in FIPS
mode. Since commit d6097b8d

 ("crypto: api - allow algs only in specific
constructions in FIPS mode") there's support for using spawns which by
itself are marked as non-approved from approved template instantiations.
So simply mark plain ghash as non-approved in testmgr to block any attempts
of direct instantiations in FIPS mode.

Signed-off-by: Nicolai Stange <nstange@suse.de>
Signed-off-by: Vladis Dronov <vdronov@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>