COMPMID-959 Add benchmark namespace in benchmark tests

Change-Id: Ieef1c5380bff1c019af0203fb7e4734f48a2fb63
Reviewed-on: https://eu-gerrit-1.euhpc.arm.com/113499
Tested-by: Jenkins <bsgcomp@arm.com>
Reviewed-by: Georgios Pinitas <georgios.pinitas@arm.com>
diff --git a/tests/benchmark/CL/SoftmaxLayer.cpp b/tests/benchmark/CL/SoftmaxLayer.cpp
index 0bdc47b..f1bc888 100644
--- a/tests/benchmark/CL/SoftmaxLayer.cpp
+++ b/tests/benchmark/CL/SoftmaxLayer.cpp
@@ -37,6 +37,8 @@
 {
 namespace test
 {
+namespace benchmark
+{
 namespace
 {
 const auto data_types = framework::dataset::make("DataType", { DataType::QASYMM8, DataType::F16, DataType::F32 });
@@ -53,5 +55,6 @@
                                 framework::dataset::combine(datasets::SoftmaxLayerLargeShapes(), data_types));
 
 TEST_SUITE_END()
+} // namespace benchmark
 } // namespace test
 } // namespace arm_compute