sonic-swss: Fix orchagent crash in generateQueueMapPerPort. (#2552)

* generateQueueMap uses m_portList[port].m_queue_ids.size to allocate  m_queueStates in FlexCounterQueueStates. But
  m_portList[port].m_queue_ids.size is zero for system ports which  results in isQueueCounterEnabled crash for system ports. Since we do   not have support disable voq counters yet, do not check   isQueueCounterEnabled for voqs.

Author: skbarista

orchagent/portsorch.cpp

@@ -6123,7 +6123,9 @@ void PortsOrch::generateQueueMapPerPort(const Port& port, FlexCounterQueueStates
         uint8_t queueRealIndex = 0;
         if (getQueueTypeAndIndex(queue_ids[queueIndex], queueType, queueRealIndex))
         {
-            if (!queuesState.isQueueCounterEnabled(queueRealIndex))
+	    /* voq counters are always enabled. There is no mechanism to disable voq
+	     * counters in a voq system. */
+            if (!voq && !queuesState.isQueueCounterEnabled(queueRealIndex))
             {
                 continue;
             }