Add support for Camellia HMAC-Based cipher suites from RFC6367

While RFC6367 focuses on Camellia-GCM cipher suites, it also adds a few
cipher suites that use SHA-2 based HMAC that can be very easily
added.

Tested against gnutls 3.3.5

Patch by: Hubert Kario <hkario@redhat.com>