Disable superVU entry and exit on !x86_32.

The assembly for this is x86_32 only so it won't work on anything else.
Disable it forcefully for now, in the future there should be a generic interpreter style fallback in place.
That will require some restructuring that isn't yet possible to do.

This requires the architecture defines to be working fully, so this can't be merged until it is fixed on the Windows side of things.