Indications are that no GF116's actually have a copy engine there, but
actually have the decompression engine. This engine can be made to do
copies, but that should be done separately.

Unclear why this didn't turn up on all GF116's, but perhaps the
non-mobile ones came with enough VRAM to not trigger ttm migrations in
test scenarios.

Fixes: https://bugs.freedesktop.org/show_bug.cgi?id=85465
Fixes: https://bugs.freedesktop.org/show_bug.cgi?id=59168
Cc: stable@vger.kernel.org
Signed-off-by: NIlia Mirkin <imirkin@alum.mit.edu>
Signed-off-by: NBen Skeggs <bskeggs@redhat.com>