Add KPI collection/submission loops to Tibit adapters

Change-Id: I5d09f59b826ac9687398688bb221f8ecdf5e1d9e
diff --git a/voltha/core/adapter_agent.py b/voltha/core/adapter_agent.py
index 748872b..5a0e1de 100644
--- a/voltha/core/adapter_agent.py
+++ b/voltha/core/adapter_agent.py
@@ -308,6 +308,7 @@
         self.event_bus.publish(topic, (logical_port_no, packet))
 
     # ~~~~~~~~~~~~~~~~~~~ Handling KPI metric submissions ~~~~~~~~~~~~~~~~~~~~~
+
     def submit_kpis(self, kpi_event_msg):
         try:
             assert isinstance(kpi_event_msg, KpiEvent)