IVGCVSW-4209 Create a public API for the ArmNN Utils

 * Moved the relevant armnnUtils headers to the new location:
   include/armnnUtils
 * Update the header usage throughout the source code

!android-nn-driver:2387

Signed-off-by: Matteo Martincigh <matteo.martincigh@arm.com>
Change-Id: I2ba15cebcacafad2b5a1a7b9c3312ffc585e09d6
diff --git a/src/backends/reference/workloads/ConvImpl.hpp b/src/backends/reference/workloads/ConvImpl.hpp
index 7dba760..562fd3e 100644
--- a/src/backends/reference/workloads/ConvImpl.hpp
+++ b/src/backends/reference/workloads/ConvImpl.hpp
@@ -13,13 +13,11 @@
 
 #include <armnn/Tensor.hpp>
 
-#include <DataLayoutIndexed.hpp>
+#include <armnnUtils/DataLayoutIndexed.hpp>
 
 #include <boost/assert.hpp>
 #include <boost/numeric/conversion/cast.hpp>
 
-#include <DataLayoutIndexed.hpp>
-
 #include <cmath>
 #include <limits>