crypto: testmgr - mark xts(aes) as fips_allowed

We (Red Hat) are intending to include dm-crypt functionality, using
xts(aes) for disk encryption, as part of an upcoming FIPS-140-2
certification effort, and xts(aes) *is* on the list of possible
mode/cipher combinations that can be certified. To make that possible, we
need to mark xts(aes) as fips_allowed in the crypto subsystem.

A 'modprobe tcrypt mode=10' in fips mode shows xts(aes) self-tests
passing successfully after this change.

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