no need to.
- Remove pmap_is_current(), pmap_[pte|l3]_valid_cacheable as there were only
used to know if we had to write back pages.
- In pmap_remove_pages(), don't bother invalidating each page in the TLB,
we're about to flush the whole TLB anyway.
This makes make world 8-9% faster on my hardware.
Reviewed by: andrew