IVGCVSW-1812 Adding Ref implementation and tests of MeanWorkloads

Change-Id: I6fb15c407024e3b91d5abf4513f8090be5821760
diff --git a/src/backends/reference/workloads/CMakeLists.txt b/src/backends/reference/workloads/CMakeLists.txt
index 7343b70..5a756e4 100644
--- a/src/backends/reference/workloads/CMakeLists.txt
+++ b/src/backends/reference/workloads/CMakeLists.txt
@@ -94,6 +94,12 @@
     Softmax.hpp
     Splitter.hpp
     TensorBufferArrayView.hpp
+    Mean.cpp
+    Mean.hpp
+    RefMeanFloat32Workload.cpp
+    RefMeanFloat32Workload.hpp
+    RefMeanUint8Workload.cpp
+    RefMeanUint8Workload.hpp
 )
 
 add_library(armnnRefBackendWorkloads STATIC ${armnnRefBackendWorkloads_sources})