Nokia Maps Suite 2.0 and its components (e.g. Maps 3.09) cannot be uninstalled. You can, however, revert to the original Maps version by reinstalling the Nokia Belle software to your phone via Nokia Suite. Connect your phone via USB to PC and select Software updates > reinstall in Nokia Suite to reinstall Nokia Belle.
If you later on want to install Nokia Maps Suite again, you can find the application at Nokia Store.