Adding infrastructure to allow sending messages between adapters
using the adapter-agent event bus.

Change-Id: Ia3654b8944745bc76f8ac4ea3c1439a082979dd4
diff --git a/voltha/adapters/broadcom_onu/broadcom_onu.py b/voltha/adapters/broadcom_onu/broadcom_onu.py
index 59fd987..b8f7d7f 100644
--- a/voltha/adapters/broadcom_onu/broadcom_onu.py
+++ b/voltha/adapters/broadcom_onu/broadcom_onu.py
@@ -68,6 +68,9 @@
         )
         self.devices_handlers = dict()  # device_id -> BroadcomOnuHandler()
 
+        # register for adapter messages
+        self.adapter_agent.register_for_inter_adapter_messages()
+
     def start(self):
         log.debug('starting')
         log.info('started')
@@ -138,6 +141,9 @@
         log.info('packet-out', logical_device_id=logical_device_id,
                  egress_port_no=egress_port_no, msg_len=len(msg))
 
+    def receive_inter_adapter_message(self, msg):
+        log.info('receive_inter_adapter_message', msg=msg)
+
 
 class BroadcomOnuHandler(object):
 
@@ -165,6 +171,7 @@
         self.proxy_address = device.proxy_address
         self.adapter_agent.register_for_proxied_messages(device.proxy_address)
 
+
         # populate device info
         device.root = True
         device.vendor = 'Broadcom'