IVGCVSW-6313 Support pre-importing outputs

 * Add ClearImportedInputs/Outputs function to IRuntime
 * Add UnImport function to ITensorHandle
 * Remove mutex from IWorkingMemHandle

Change-Id: I34c9b6e1618755e10f3b4597afa1d9a9ea97e5fe
Signed-off-by: Finn Williams <finwil01@e127804.cambridge.arm.com>
diff --git a/include/armnn/Types.hpp b/include/armnn/Types.hpp
index 02f265c..7f2e192 100644
--- a/include/armnn/Types.hpp
+++ b/include/armnn/Types.hpp
@@ -263,6 +263,8 @@
 /// Type of identifiers for bindable layers (inputs, outputs).
 using LayerBindingId = int;
 using ImportedInputId = unsigned int;
+using ImportedOutputId = unsigned int;
+
 
 class PermutationVector
 {