MMU: disable BAT resolution

No known games, not even Wii MMU games like Cars 2 and Toy Story 3, use custom
BATs. This makes BAT resolution a waste of time. BAT handling could be
optimized significantly, but as long as nothing uses it, it's easier to just
disable it.

Should significantly improve performance in MMU-heavy games.
Merge pull request #1283 from FioraAeterna/removebats

MMU: disable BAT resolution