Fix IoConfigEvent constructor initializer list

Fortunately this bug never showed up, because the parameter
field has not been used yet.

Change-Id: I2b36e2b7e1dcc2039c494fc5ea4994d262435aac
diff --git a/services/audioflinger/Threads.h b/services/audioflinger/Threads.h
index 8df6f94..bf88517 100644
--- a/services/audioflinger/Threads.h
+++ b/services/audioflinger/Threads.h
@@ -65,7 +65,7 @@
     class IoConfigEvent : public ConfigEvent {
     public:
         IoConfigEvent(int event, int param) :
-            ConfigEvent(CFG_EVENT_IO), mEvent(event), mParam(event) {}
+            ConfigEvent(CFG_EVENT_IO), mEvent(event), mParam(param) {}
         virtual ~IoConfigEvent() {}
 
                 int event() const { return mEvent; }