nvkm_volt_new_
ret = nvkm_volt_new_(&gf100_volt, device, type, inst, &volt);
ret = nvkm_volt_new_(&gf117_volt, device, type, inst, &volt);
ret = nvkm_volt_new_(&nv40_volt, device, type, inst, &volt);
int nvkm_volt_new_(const struct nvkm_volt_func *, struct nvkm_device *, enum nvkm_subdev_type, int,