COMPMID-417: Remove val_to_string

The function was a duplicate of the to_string function we have in
support/ToolchainSupport.h

Change-Id: If1eff674333248f7d189824ced717310afec19b0
Reviewed-on: http://mpd-gerrit.cambridge.arm.com/79634
Reviewed-by: Georgios Pinitas <georgios.pinitas@arm.com>
Tested-by: Kaizen <jeremy.johnson+kaizengerrit@arm.com>
diff --git a/src/core/CL/kernels/CLMinMaxLocationKernel.cpp b/src/core/CL/kernels/CLMinMaxLocationKernel.cpp
index 939a53b..8a49320 100644
--- a/src/core/CL/kernels/CLMinMaxLocationKernel.cpp
+++ b/src/core/CL/kernels/CLMinMaxLocationKernel.cpp
@@ -66,8 +66,8 @@
     // Set kernel build options
     std::set<std::string> build_opts;
     build_opts.emplace("-DDATA_TYPE=" + get_cl_type_from_data_type(input->info()->data_type()));
-    build_opts.emplace("-DDATA_TYPE_MAX=" + val_to_string<int>(_data_type_max_min[0]));
-    build_opts.emplace("-DDATA_TYPE_MIN=" + val_to_string<int>(_data_type_max_min[1]));
+    build_opts.emplace("-DDATA_TYPE_MAX=" + support::cpp11::to_string(_data_type_max_min[0]));
+    build_opts.emplace("-DDATA_TYPE_MIN=" + support::cpp11::to_string(_data_type_max_min[1]));
     build_opts.emplace((0 != (num_elems_processed_per_iteration % max_cl_vector_width)) ? "-DNON_MULTIPLE_OF_16" : "");
 
     // Create kernel