drm/nouveau/sec2/tu102-: prepare for GSP-RM

- add (initial) R535 implementation of SEC2, needed for boot

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230918202149.4343-30-skeggsb@gmail.com