kernel - VM rework part 18 - Cleanup
* Significantly reduce the zone limit for pvzone (for pmap
pv_entry structures). pv_entry's are no longer allocated
on a per-page basis so the limit can be made much smaller.
This also has the effect of reducing the per-cpu cache limit
which ultimately stabilizes wired memory use for the zone.
* Also reduce the generic pre-cpu cache limit for zones.
This only really effects the pvzone.
* Make pvzone, mapentzone, and swap_zone __read_mostly.
* Enhance vmstat -z, report current structural use and actual
total memory use.
* Also cleanup the copyright statement for vm/vm_zone.c. John Dyson's
original copyright was slightly different than the BSD copyright and
stipulated no changes, so separate out the DragonFly addendum.