COMPMID-417: Fix clang-tidy failures for 32-bit runs

Change-Id: I2fbb6dda1c281627a4d64dce3b4c4d2ebaa8d022
Reviewed-on: http://mpd-gerrit.cambridge.arm.com/89289
Reviewed-by: Pablo Tello <pablo.tello@arm.com>
Tested-by: Kaizen <jeremy.johnson+kaizengerrit@arm.com>
Reviewed-by: Anthony Barbier <anthony.barbier@arm.com>
diff --git a/src/core/NEON/kernels/NENormalizationLayerKernel.cpp b/src/core/NEON/kernels/NENormalizationLayerKernel.cpp
index b444c9d..fc3f5f2 100644
--- a/src/core/NEON/kernels/NENormalizationLayerKernel.cpp
+++ b/src/core/NEON/kernels/NENormalizationLayerKernel.cpp
@@ -70,6 +70,7 @@
     _border_size   = BorderSize(0, border_width);
 
     unsigned int num_elems_processed_per_iteration = 16 / input->info()->element_size();
+    ARM_COMPUTE_UNUSED(num_elems_processed_per_iteration);
 
     switch(_input->info()->data_type())
     {