modem: print call ID during log of call state

Change-Id: I33d0153b3e89aa1924129b8068ef068c08059958
diff --git a/src/osmo_gsm_tester/modem.py b/src/osmo_gsm_tester/modem.py
index 5106702..6a2a49a 100644
--- a/src/osmo_gsm_tester/modem.py
+++ b/src/osmo_gsm_tester/modem.py
@@ -735,7 +735,7 @@
             self.log('asking call state for non existent call')
             log.log_exn()
             state = 'disconnected'
-        self.dbg('call state: %s' % state)
+        self.dbg('call state: %s' % state, call_id=call_id)
         return state
 
     def _on_callmgr_call_added(self, obj_path, properties):