drm/nouveau/core: object.engine is always a nouveau_engine now

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
diff --git a/drivers/gpu/drm/nouveau/core/engine/device/base.c b/drivers/gpu/drm/nouveau/core/engine/device/base.c
index 0a6abc2..f74f9cb 100644
--- a/drivers/gpu/drm/nouveau/core/engine/device/base.c
+++ b/drivers/gpu/drm/nouveau/core/engine/device/base.c
@@ -516,7 +516,7 @@
 		while (device && device->parent)
 			device = device->parent;
 	} else {
-		device = nv_object(obj)->engine;
+		device = &nv_object(obj)->engine->subdev.object;
 		if (device && device->parent)
 			device = device->parent;
 	}