DolphinWX: Change "AM-Baseboard" string to "AM Baseboard"

It's so that the string in ControllerConfigDiag will match the string
in GameCubeConfigPane. Right now, it unnecessarily appears twice in
the list of strings to translate.

Source/Core/DolphinWX/ControllerConfigDiag.cpp

@@ -51,7 +51,7 @@ ControllerConfigDiag::ControllerConfigDiag(wxWindow* const parent)
 		_("TaruKonga (Bongos)"),
 		_("GBA"),
 		_("Keyboard"),
-		_("AM-Baseboard")
+		_("AM Baseboard")
 	}};
 
 	wxBoxSizer* const main_sizer = new wxBoxSizer(wxVERTICAL);