IVGCVSW-2379 Add Greater Ref workload implementation

 * Added the Greater operation as an element-wise workload
 * Added the unit tests

Change-Id: Ie00ee30e47a5f5e17a728032eeb11a085d06c8f2
diff --git a/src/backends/reference/RefWorkloadFactory.cpp b/src/backends/reference/RefWorkloadFactory.cpp
index 8173bbb..eb8807e 100644
--- a/src/backends/reference/RefWorkloadFactory.cpp
+++ b/src/backends/reference/RefWorkloadFactory.cpp
@@ -303,7 +303,7 @@
 std::unique_ptr<IWorkload> RefWorkloadFactory::CreateGreater(const GreaterQueueDescriptor& descriptor,
                                                              const WorkloadInfo& info) const
 {
-    return MakeWorkload<NullWorkload, NullWorkload>(descriptor, info);
+    return MakeWorkload<RefGreaterFloat32Workload, RefGreaterUint8Workload>(descriptor, info);
 }
 
 std::unique_ptr<IWorkload> RefWorkloadFactory::CreateDebug(const DebugQueueDescriptor& descriptor,