Added explicit sycl::plus

Author: maximdimakov

sycl/test/on-device/back_to_back_collectives.cpp

@@ -47,9 +47,9 @@ int main() {
         auto g = it.get_group();
         // Loop to increase number of back-to-back calls
         for (int r = 0; r < 10; ++r) {
-          Sum[i] = reduce(g, Input[i], plus<>());
-          EScan[i] = exclusive_scan(g, Input[i], plus<>());
-          IScan[i] = inclusive_scan(g, Input[i], plus<>());
+          Sum[i] = reduce(g, Input[i], sycl::plus<>());
+          EScan[i] = exclusive_scan(g, Input[i], sycl::plus<>());
+          IScan[i] = inclusive_scan(g, Input[i], sycl::plus<>());
         }
       });
     });