drm/nouveau/mmu: switch to instanced constructor

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>

drm/nouveau/mmu/gp100-: support vmms with gcc/tex replayable faults enabled

Some GPU units are capable of supporting "replayable" page faults, where
the execution unit will wait for SW to fixup GPU page tables rather than
triggering a channel-fatal fault.

This feature isn't useful (it's harmful, even) unless something like HMM
is being used to manage events appearing in the replayable fault buffer,
so, it's disabled by default.

This commit allows a client to request it be enabled.

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

drm/nouveau/mmu/gv100: initial support

VEID support hacked in here, as it's the most convenient place for now.

Will be refined once it's better understood.

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