drm/nouveau: fix nouveau_mm/nouveau_mm_node leak

v2: use already existing parent
Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/core/core/gpuobj.c

@@ -39,6 +39,11 @@ nouveau_gpuobj_destroy(struct nouveau_gpuobj *gpuobj)
 			nv_wo32(gpuobj, i, 0x00000000);
 	}
 
+	if (gpuobj->node) {
+		nouveau_mm_free(&nv_gpuobj(gpuobj->parent)->heap,
+				&gpuobj->node);
+	}
+
 	if (gpuobj->heap.block_size)
 		nouveau_mm_fini(&gpuobj->heap);