Switch to using PAs rather than VAs for the addresses we map for
devices. This is a nop, except for what's reported by atmelbus for the
resources.

It would be nice if we could dymanically allocated these things, but
the pmap_mapdev panics if we don't keep the static mappings, so we
still need to play the carefully allocate VA space between all
supported SoC game.

User's with their own devices may need to make adjustments.