IOS: Simplify IPC initialisation

The extra IPC ack is triggered by a syscall that is invoked in ES's
main function; the syscall literally just sets Y2, IX1 and IX2 in
HW_IPC_ARMCTRL -- there is no complicated ack queue or anything.

Source/Core/Core/IOS/ES/ES.cpp

@@ -122,6 +122,8 @@ void ESDevice::FinalizeEmulationState()
 
 void ESDevice::FinishInit()
 {
+  m_ios.InitIPC();
+
   if (s_title_to_launch != 0)
   {
     NOTICE_LOG_FMT(IOS, "Re-launching title after IOS reload.");