MT#63071 AmSessionContainer: use static_cast for up-cast

Use static_cast for the up-cast of AmSession.

Static cast is equivalent to the C-style implicit cast,
when doing an up-cast, but C-style cast is less clear.

So just use static_cast here.

Change-Id: I7a41f2ee389a4bd48734a75a0d736d8d5a75ed28

core/AmSessionContainer.cpp

@@ -585,7 +585,7 @@ AmSessionContainer::addSession(const string& callid,
     return ShutDown;
   
   if(AmEventDispatcher::instance()->
-     addEventQueue(local_tag,(AmEventQueue*)session,
+     addEventQueue(local_tag,static_cast<AmEventQueue*>(session),
 		   callid,remote_tag,via_branch)) {
     return Inserted;
   }
@@ -601,7 +601,7 @@ AmSessionContainer::addSession(const string& local_tag,
     return ShutDown;
 
   if(AmEventDispatcher::instance()->
-     addEventQueue(local_tag,(AmEventQueue*)session)){
+     addEventQueue(local_tag,static_cast<AmEventQueue*>(session))){
     return Inserted;
   }