Fix building with PCH disabled.

Source/Core/Core/ARDecrypt.cpp

@@ -7,6 +7,7 @@
 // Copyright (C) 2003-2004 Parasyte
 
 #include <algorithm>
+#include <cstring>
 
 #ifdef _WIN32
 #include <windows.h>

Source/Core/Core/HW/SI_DeviceAMBaseboard.cpp

@@ -2,6 +2,8 @@
 // Licensed under GPLv2
 // Refer to the license.txt file included.
 
+#include <cstring>
+
 #include "Common/MsgHandler.h"
 #include "Common/Logging/Log.h"