kernel - VM rework part 15 - Core pmap work, refactor PG_*
* Augment PG_FICTITIOUS. This takes over some of PG_UNMANAGED's previous
capabilities. In addition, the pmap_*() API will work with fictitious
pages, making mmap() operation (aka of the GPU) more consistent.
* Add PG_UNQUEUED. This prevents a vm_page from being manipulated in
the vm_page_queues[] in any way. This takes over another feature
of the old PG_UNMANAGED flag.
* Remove PG_UNMANAGED
* Remove PG_DEVICE_IDX. This is no longer relevant. We use PG_FICTITIOUS
for all device pages.
* Refactor vm_contig_pg_alloc(), vm_contig_pg_free(),
vm_page_alloc_contig(), and vm_page_free_contig().
These functions now set PG_FICTITIOUS | PG_UNQUEUED on the returned
pages, and properly clear the bits upon free or if/when a regular
(but special contig-managed) page is handed over to the normal paging
system.
This is combined with making the pmap*() functions work better with
PG_FICTITIOUS is the primary 'fix' for some of DRMs hacks.
UnifiedSplitRaw
