drm/nouveau/core: add nvkm_subdev_new_() for bare subdevs

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

drivers/gpu/drm/nouveau/include/nvkm/core/subdev.h

@@ -24,6 +24,8 @@ struct nvkm_subdev_func {
 };
 
 extern const char *nvkm_subdev_name[NVKM_SUBDEV_NR];
+int nvkm_subdev_new_(const struct nvkm_subdev_func *, struct nvkm_device *,
+		     int index, struct nvkm_subdev **);
 void nvkm_subdev_ctor(const struct nvkm_subdev_func *, struct nvkm_device *,
 		      int index, struct nvkm_subdev *);
 void nvkm_subdev_del(struct nvkm_subdev **);

drivers/gpu/drm/nouveau/nvkm/core/subdev.c

@@ -221,3 +221,14 @@ nvkm_subdev_ctor(const struct nvkm_subdev_func *func,
 	__mutex_init(&subdev->mutex, name, &nvkm_subdev_lock_class[index]);
 	subdev->debug = nvkm_dbgopt(device->dbgopt, name);
 }
+
+int
+nvkm_subdev_new_(const struct nvkm_subdev_func *func,
+		 struct nvkm_device *device, int index,
+		 struct nvkm_subdev **psubdev)
+{
+	if (!(*psubdev = kzalloc(sizeof(**psubdev), GFP_KERNEL)))
+		return -ENOMEM;
+	nvkm_subdev_ctor(func, device, index, *psubdev);
+	return 0;
+}