Fix build using gcc-5

It seems the compiler was interpreting 'DataType' as the template argument
rather than the type name. By fully qualifying the type name, it avoids
this ambiguity.

Change-Id: Iab00b0a22390417a5a6b22c829a171152f2da495
Signed-off-by: Rob Hughes <robert.hughes@arm.com>
diff --git a/src/backends/reference/test/RefCreateWorkloadTests.cpp b/src/backends/reference/test/RefCreateWorkloadTests.cpp
index 6dbbd55..c46a9e5 100644
--- a/src/backends/reference/test/RefCreateWorkloadTests.cpp
+++ b/src/backends/reference/test/RefCreateWorkloadTests.cpp
@@ -1282,8 +1282,8 @@
     // new input and output tensor handlers are created and then replace in the workload
     shared_ptr<RefMemoryManager> memoryManager = make_shared<RefMemoryManager>();
     const RefTensorHandleFactory tensorHandleFactory(memoryManager);
-    TensorInfo inputInfo({2 , 2}, DataType::Float16);
-    TensorInfo outputInfo({2 , 2}, DataType::Float16);
+    TensorInfo inputInfo({2 , 2}, armnn::DataType::Float16);
+    TensorInfo outputInfo({2 , 2}, armnn::DataType::Float16);
     unique_ptr<ITensorHandle> inputHandle  = tensorHandleFactory.CreateTensorHandle(inputInfo);
     unique_ptr<ITensorHandle> outputHandle = tensorHandleFactory.CreateTensorHandle(outputInfo);
     unsigned int slot = 0;