Bugfix: Fix cl_ext.h include path in CL backend

Signed-off-by: Francis Murtagh <francis.murtagh@arm.com>
Change-Id: I560c9f6297e9552bab26a6f88765830409be78c3
diff --git a/src/backends/cl/ClImportTensorHandle.hpp b/src/backends/cl/ClImportTensorHandle.hpp
index ddd20fc..752f793 100644
--- a/src/backends/cl/ClImportTensorHandle.hpp
+++ b/src/backends/cl/ClImportTensorHandle.hpp
@@ -19,7 +19,7 @@
 #include <arm_compute/core/TensorShape.h>
 #include <arm_compute/core/Coordinates.h>
 
-#include <include/CL/cl_ext.h>
+#include <CL/cl_ext.h>
 #include <arm_compute/core/CL/CLKernelLibrary.h>
 
 namespace armnn