IVGCVSW-1065 Allow MODEL_OUTPUT as input to another layer

Change-Id: I24fe0916847ec713abf952b9ea911693a692d440
diff --git a/ConversionUtils.hpp b/ConversionUtils.hpp
index 783f7ce..597edc4 100644
--- a/ConversionUtils.hpp
+++ b/ConversionUtils.hpp
@@ -800,6 +800,7 @@
     {
         case OperandLifeTime::TEMPORARY_VARIABLE: // intentional fallthrough
         case OperandLifeTime::MODEL_INPUT:
+        case OperandLifeTime::MODEL_OUTPUT:
         {
             // The tensor is either an operand internal to the model, or a model input.
             // It can be associated with an ArmNN output slot for an existing layer.