Revert the changes made in rev 1.82. It is important to use pmap_enter(9)

Revert the changes made in rev 1.82.  It is important to use pmap_enter(9)
and pmap_remove(9) here since we're dealing with managed pages here.  Found
out the hard way by deraadt@ on landisk where we're running into issues
with virtual cache aliases because multiple mappings exist for the
pages we're dealing with here.  The pmap_enter(9) and pmap_remove(9)
functions handle conflicting cache aliases, whereas pmap_map_direct(9) and
pmap_kenter_pa(9) assume that the pages is exclusively mapped in the kernel
pmap.

ok deraadt@