drm/nouveau/fault: expose replayable fault buffer event class

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

drm/nouveau/fault/gp100: expose MaxwellFaultBufferA

This nvclass exposes the replayable fault buffer, which will be used
by SVM to manage GPU page faults.

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