Fixing size ofr allowed gRPC response in teardown

Change-Id: I709803af2b5239370d2d6755d3605d8fc1bc6d5d
diff --git a/tests/scale/Voltha_Scale_Tests.robot b/tests/scale/Voltha_Scale_Tests.robot
index 8a70340..93a31e4 100755
--- a/tests/scale/Voltha_Scale_Tests.robot
+++ b/tests/scale/Voltha_Scale_Tests.robot
@@ -254,7 +254,7 @@
     [Documentation]  Disable and delete the OLTs in VOLTHA
     [Tags]      non-critical    teardown
 
-    ${rc}    ${output}=     Run And Return Rc And Output    voltctl -c ${VOLTCTL_CONFIG} device list -f Type=openolt -q
+    ${rc}    ${output}=     Run And Return Rc And Output    voltctl -c ${VOLTCTL_CONFIG} device list -m 32MB -f Type=openolt -q
     Should Be Equal As Integers    ${rc}    0   Failed to get device list from voltctl: ${output}
     Log     ${output}
     ${devices}=     Split To Lines  ${output}