DolphinWX: Make WXInputBase part of the WxUtils namespace.

There's no need for the preprocessor checks for wx, since this is used in wx code. Also, this being a part of the InputCommon namespace is kind of wrong.

Source/Core/DolphinWX/WXInputBase.h

@@ -4,14 +4,10 @@
 
 #pragma once
 
-#if defined(HAVE_WX) && HAVE_WX
 #include <wx/string.h>
-#endif
 
-namespace InputCommon
+namespace WxUtils
 {
-#if defined(HAVE_WX) && HAVE_WX
 const wxString WXKeyToString(int keycode);
 const wxString WXKeymodToString(int modifier);
-#endif
 }