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/Decoders.hpp b/src/backends/reference/workloads/Decoders.hpp
index dcd498c..b9cd7f9 100644
--- a/src/backends/reference/workloads/Decoders.hpp
+++ b/src/backends/reference/workloads/Decoders.hpp
@@ -6,8 +6,9 @@
 #pragma once
 
 #include "BaseIterator.hpp"
-#include "FloatingPointConverter.hpp"
-#include "TensorUtils.hpp"
+
+#include <armnnUtils/FloatingPointConverter.hpp>
+#include <armnnUtils/TensorUtils.hpp>
 
 #include <boost/assert.hpp>