fix CMakeLists.txt

src/metric/elementwise_metric.cu

@@ -97,6 +97,7 @@ PackedReduceResult Reduce(Context const* ctx, MetaInfo const& info, Fn&& loss) {
     dh::XGBCachingDeviceAllocator<char> alloc;
     thrust::counting_iterator<size_t> begin(0);
     thrust::counting_iterator<size_t> end = begin + labels.Size();
+
     result = thrust::transform_reduce(
         thrust::hip::par(alloc), begin, end,
         [=] XGBOOST_DEVICE(size_t i) {