Clean up header usage a bit in NEON backend

Including NEFunctions.h is unnecessary and adds about a second
to compile time each translation unit in which it appears,
so we should use just the header file with the arm compute function
declarations that we need.

Signed-off-by: Matthew Bentham <matthew.bentham@arm.com>
Change-Id: I605d0eb82ccf2aafa35381a5d9d54337d3fe17a7
diff --git a/src/backends/neon/workloads/NeonSplitterWorkload.hpp b/src/backends/neon/workloads/NeonSplitterWorkload.hpp
index f902566..66349f9 100644
--- a/src/backends/neon/workloads/NeonSplitterWorkload.hpp
+++ b/src/backends/neon/workloads/NeonSplitterWorkload.hpp
@@ -7,7 +7,8 @@
 
 #include <backendsCommon/Workload.hpp>
 
-#include <arm_compute/runtime/NEON/NEFunctions.h>
+#include <arm_compute/core/Error.h>
+#include <arm_compute/runtime/IFunction.h>
 
 #include <functional>
 
@@ -26,7 +27,7 @@
     void Execute() const override;
 
 private:
-    mutable std::unique_ptr<arm_compute::NESplit> m_Layer;
+    mutable std::unique_ptr<arm_compute::IFunction> m_Layer;
 };
 
 } //namespace armnn