drm/nouveau/mmu: Add correct turing page kinds

Turing introduced a new simplified page kind
scheme, reducing the number of possible page
kinds from 256 to 16.  It also is the first
NVIDIA GPU in which the highest possible page
kind value is not reserved as an "invalid" page
kind.

To address this, the invalid page kind is made
an explicit property of the MMU HAL, and a new
table of page kinds is added to the tu102 MMU
HAL.

One hardware change not addressed here is that
0x00 is technically no longer a supported page
kind, and pitch surfaces are instead intended to
share the block-linear generic page kind 0x06.
However, because that will be a rather invasive
change to nouveau and 0x00 still works fine in
practice on Turing hardware, addressing this new
behavior is deferred.

Signed-off-by: James Jones <jajones@nvidia.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>