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/SpaceToBatchNdTestImpl.cpp b/src/backends/backendsCommon/test/layerTests/SpaceToBatchNdTestImpl.cpp
index ea2130d..2793875 100644
--- a/src/backends/backendsCommon/test/layerTests/SpaceToBatchNdTestImpl.cpp
+++ b/src/backends/backendsCommon/test/layerTests/SpaceToBatchNdTestImpl.cpp
@@ -32,6 +32,7 @@
     const float qScale = 1.0f,
     const int32_t qOffset = 0)
 {
+    boost::ignore_unused(memoryManager);
     const armnn::PermutationVector NCHWToNHWC = {0, 3, 1, 2};
     if (descriptor.m_Parameters.m_DataLayout == armnn::DataLayout::NHWC)
     {