eventq: convert all usage of events to use the new API.

For now, there is still a single global event queue, but this is
necessary for making the steps towards a parallelized m5.

src/dev/etherbus.hh

@@ -59,8 +59,7 @@ class EtherBus : public EtherObject
         EtherBus *bus;
 
       public:
-        DoneEvent(EventQueue *q, EtherBus *b)
-            : Event(q), bus(b) {}
+        DoneEvent(EtherBus *b) : bus(b) {}
         virtual void process() { bus->txDone(); }
         virtual const char *description() const
             { return "ethernet bus completion"; }