Less code duplication in HAL 1.2

Signed-off-by: Derek Lamberti <derek.lamberti@arm.com>
Change-Id: Ic2e8964745a4323efb1e06d466c0699f17a70c55
diff --git a/ArmnnDriverImpl.hpp b/ArmnnDriverImpl.hpp
index c5b1778..dfaafb3 100644
--- a/ArmnnDriverImpl.hpp
+++ b/ArmnnDriverImpl.hpp
@@ -23,6 +23,13 @@
 namespace armnn_driver
 {
 
+template <typename Callback, typename Context>
+struct CallbackContext
+{
+    Callback callback;
+    Context ctx;
+};
+
 template<typename HalPolicy>
 class ArmnnDriverImpl
 {