COMPMID-920: Introduce prepare() stage

Change-Id: I08ddb7f6e061178e7566518b48e4e18f8f078596
Reviewed-on: https://eu-gerrit-1.euhpc.arm.com/129825
Tested-by: Jenkins <bsgcomp@arm.com>
Reviewed-by: Anthony Barbier <anthony.barbier@arm.com>
diff --git a/src/graph/Workload.cpp b/src/graph/Workload.cpp
index c53a8a4..f350bbf 100644
--- a/src/graph/Workload.cpp
+++ b/src/graph/Workload.cpp
@@ -37,5 +37,13 @@
         task->run();
     }
 }
+
+void ExecutionTask::prepare()
+{
+    if(task)
+    {
+        task->prepare();
+    }
+}
 } // namespace graph
 } // namespace arm_compute
\ No newline at end of file