IVGCVSW-4246 Clean build Layers with -Wextra

Change-Id: I649cd2304fb0040164763d31a12fc77c6c3bed87
Signed-off-by: Derek Lamberti <derek.lamberti@arm.com>
diff --git a/src/backends/backendsCommon/test/OptimizedNetworkTests.cpp b/src/backends/backendsCommon/test/OptimizedNetworkTests.cpp
index cbe74b8..2df4c8f 100644
--- a/src/backends/backendsCommon/test/OptimizedNetworkTests.cpp
+++ b/src/backends/backendsCommon/test/OptimizedNetworkTests.cpp
@@ -263,7 +263,7 @@
     {
         BOOST_CHECK(layer->GetBackendId() == armnn::Compute::CpuRef);
         BOOST_CHECK_NO_THROW(
-            layer->CreateWorkload(static_cast<armnn::OptimizedNetwork*>(optNet.get())->GetGraph(), fact));
+            layer->CreateWorkload(fact));
     }
 }