drm/nouveau/xtensa: cosmetic changes

This is purely preparation for upcoming commits, there should be no
code changes here.

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

drivers/gpu/drm/nouveau/include/nvkm/engine/xtensa.h

@@ -4,7 +4,7 @@
 struct nvkm_gpuobj;
 
 struct nvkm_xtensa {
-	struct nvkm_engine base;
+	struct nvkm_engine engine;
 
 	u32 addr;
 	struct nvkm_gpuobj *gpu_fw;

drivers/gpu/drm/nouveau/nvkm/engine/xtensa.c

@@ -100,7 +100,7 @@ _nvkm_xtensa_init(struct nvkm_object *object)
 	int i, ret;
 	u32 tmp;
 
-	ret = nvkm_engine_init(&xtensa->base);
+	ret = nvkm_engine_init(&xtensa->engine);
 	if (ret)
 		return ret;
 
@@ -167,5 +167,5 @@ _nvkm_xtensa_fini(struct nvkm_object *object, bool suspend)
 	if (!suspend)
 		nvkm_gpuobj_ref(NULL, &xtensa->gpu_fw);
 
-	return nvkm_engine_fini(&xtensa->base, suspend);
+	return nvkm_engine_fini(&xtensa->engine, suspend);
 }