INES Mapper 210

This mapper represents the NAMCOT-175 board, used for Wagyan 2 and Splatterhouse 2. It is very similar to iNES Mapper 019, having a Namco 106 with no N163 expansion sound.

The original intent for this mapper is that it has hardwired mirroring (like TFROM); subsequent research questions whether this is actually necessary, and that games seem to only rely on a well-defined default mirroring (which should be set in the iNES header, but is expected always to be vertical, due to the practical necessity of the mirroring being implemented through uniform Namco 106 registers default values)