NetPlayClient: Remove unused macro

Source/Core/Core/NetPlayClient.cpp

@@ -21,8 +21,6 @@ static std::mutex crit_netplay_client;
 static NetPlayClient * netplay_client = nullptr;
 NetSettings g_NetPlaySettings;
 
-#define RPT_SIZE_HACK  (1 << 16)
-
 NetPad::NetPad()
 {
 	nHi = 0x00808080;