sim: Remove declaration of unused CountedDrainEvent

The CountedDrainEvent event was used to keep track of objects that
required additional simulation to drain. It was removed as a part of
the great drain rewrite, but the declaration remained.

Change-Id: I767a3213669040d3f27e2afafa2e4a5bb997e325
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Curtis Dunham <curtis.dunham@arm.com>

src/sim/sim_events.hh

@@ -98,22 +98,6 @@ class LocalSimLoopExitEvent : public Event
                                               const std::string &section);
 };
 
-class CountedDrainEvent : public Event
-{
-  private:
-    // Count of how many objects have not yet drained
-    int count;
-
-  public:
-    CountedDrainEvent();
-
-    void process() override;
-
-    void setCount(int _count) { count = _count; }
-
-    int getCount() const { return count; }
-};
-
 //
 // Event class to terminate simulation after 'n' related events have
 // occurred using a shared counter: used to terminate when *all*