Implement AES-GCM-SIV
This implements AES-GCM-SIV, described in RFC8452, on top of the existing AES-GCM primitives. In particular, its hash algorithm POLYVAL is implemented using the GHASH with additional byte order conversion according to RFC8452 Appendix A.
Signed-off-by: Daiki Ueno dueno@redhat.com