Still the same code, but not an "engine" anymore.  The fence code is more of
a policy decision rather than exposing mechanisms, so it's not appropriate
to port it to the new engine subsystem.
Signed-off-by: NBen Skeggs <bskeggs@redhat.com>

v2 (Ben Skeggs):
- some fixes for 64KiB PAGE_SIZE
- fix porting issues in (currently unused) nv41/nv44 pciegart code
Signed-off-by: NBen Skeggs <bskeggs@redhat.com>

Future work will be headed in the way of separating the policy supplied by
the nouveau drm module from the mechanisms provided by the driver core.

There will be a couple of major classes (subdev, engine) of driver modules
that have clearly defined tasks, and the further directory structure change
is to reflect this.

No code changes here whatsoever, aside from fixing up a couple of include
file pathnames.
Signed-off-by: NBen Skeggs <bskeggs@redhat.com>

Been tested on each major revision that's relevant here, but I'm sure there
are still bugs waiting to be ironed out.

This is a *very* invasive change.

There's a couple of pieces left that I don't like much (eg. other engines
using fifo_priv for the channel count), but that's an artefact of there
being a master channel list still.  This is changing, slowly.
Signed-off-by: NBen Skeggs <bskeggs@redhat.com>

Signed-off-by: NBen Skeggs <bskeggs@redhat.com>

Now have a somewhat simpler semaphore sync implementation for nv17:nv84,
and a switched to using semaphores as fences on nv84+ and making use of
the hardware's >= acquire operation.
Signed-off-by: NBen Skeggs <bskeggs@redhat.com>