drm/nouveau/pmu: switch to instanced constructor

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

drm/nouveau/pmu: initialise SW state for falcon from constructor

This will allow us to register the falcon with ACR, and further customise
its behaviour by providing the nvkm_falcon_func structure directly.

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

drm/nouveau/pmu: select implementation based on available firmware

This will allow for further customisation of the subdev depending on what
firmware is available.

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

drm/nouveau/pmu/gt215-: abstract detection of whether reset is needed

GT215, GF100-GP100, and GP10x are all different.

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

drm/nouveau/pmu/gt215: fix reset

The NV_PMC_ENABLE bit for PMU did not appear until GF100, and some other
unknown register needs to be poked instead.

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

drm/nouveau/pmu: move ucode handling into gt215 implementation

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

drm/nouveau/pmu: convert to new-style nvkm_subdev

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