Building ONU list per OLT

Change-Id: I9b56b5d7df2601fabe90652f6b15c7bf789334a2
diff --git a/tests/dt-workflow/Voltha_DT_PODTests.robot b/tests/dt-workflow/Voltha_DT_PODTests.robot
index ce8409a..36ff38b 100644
--- a/tests/dt-workflow/Voltha_DT_PODTests.robot
+++ b/tests/dt-workflow/Voltha_DT_PODTests.robot
@@ -268,7 +268,7 @@
         ...    ${olt_device_id}
         ${List_ONU_Serial}    Create List
         Set Suite Variable    ${List_ONU_Serial}
-        Build ONU SN List    ${List_ONU_Serial}    ${num_onus}
+        Build ONU SN List    ${List_ONU_Serial}    ${num_onus}    ${olt_serial_number}
         Log    ${List_ONU_Serial}
         Run Keyword    Wait Until Keyword Succeeds    ${timeout}    5s    Validate ONU Flows
         ...    ${List_ONU_Serial}    ${onu_flows}