message: fix compilation issue with disabled CUDA
diff: @@ -156,10 +156,11 @@ scoped_device_id_guard::scoped_device_id_guard(const CudaExecutor* exec,
  namespace log {
  -void init_nvtx(const char*, profile_event_category) GKO_NOT_COMPILED(cuda);
  +void init_nvtx() GKO_NOT_COMPILED(cuda);
  -void begin_nvtx(const char*, profile_event_category) GKO_NOT_COMPILED(cuda);
  +std::function<void(const char*, profile_event_category)> begin_nvtx_fn(
  + uint32_t color_rgb) GKO_NOT_COMPILED(cuda);
  void end_nvtx(const char*, profile_event_category) GKO_NOT_COMPILED(cuda);
  