[VOL-2778] Support for TT workflow in the scale test

Change-Id: I76b850593e17ffb2781fbc169f20ecb611937811
diff --git a/tests/scale/Voltha_Scale_Tests.robot b/tests/scale/Voltha_Scale_Tests.robot
index e5f7153..b649378 100644
--- a/tests/scale/Voltha_Scale_Tests.robot
+++ b/tests/scale/Voltha_Scale_Tests.robot
@@ -164,7 +164,7 @@
 Wait for subscribers to have an IP
     [Documentation]    Check that all subscribers have received a DHCP_ACK
     [Tags]      non-critical    dhcp  plot-onos-dhcp
-    Wait for DHCP Ack     ${onos_ssh_connection}  ${total_onus}
+    Wait for DHCP Ack     ${onos_ssh_connection}  ${total_onus}     ${workflow}
 
 Disable and Delete devices
     [Documentation]  Disable and delete the OLTs in VOLTHA