IVGCVSW-4246 Clean build of LayerTests with -Wextra

Change-Id: If3d98e45a6e2fa8e1afd19a4052334335feacf63
Signed-off-by: Derek Lamberti <derek.lamberti@arm.com>
diff --git a/src/backends/backendsCommon/test/layerTests/FakeQuantizationTestImpl.cpp b/src/backends/backendsCommon/test/layerTests/FakeQuantizationTestImpl.cpp
index 1ce9d2d..d25673b 100644
--- a/src/backends/backendsCommon/test/layerTests/FakeQuantizationTestImpl.cpp
+++ b/src/backends/backendsCommon/test/layerTests/FakeQuantizationTestImpl.cpp
@@ -18,6 +18,7 @@
     armnn::IWorkloadFactory& workloadFactory,
     const armnn::IBackendInternal::IMemoryManagerSharedPtr& memoryManager)
 {
+    boost::ignore_unused(memoryManager);
     constexpr unsigned int width = 2;
     constexpr unsigned int height = 3;