Add some hash types for UDP RSS for both IPv4 and IPv6.

Nothing is yet using this but I'd like to reserve these values.
Add RSS hashing awareness for IPv6 and TCP IPv6 hash types.
Add the IPv6 versions of the multi-bind, hash/hash type and RSS options.
Add INP_RSS_BUCKET_SET awareness for IPv6 pcbgroup entries.

This ensures that a listen socket with INP_RSS_BUCKET_SET set will use
the pre-determined PCBGROUP rather than what the hashing path chooses.
Add IPv6 flowid, bindmulti and RSS awareness.