Remove add_menu()’s second argument from it’s submenus list

Try this:

    add_menu_page( 'MDW Config', 'MDW Config', 'manage_options', 'mdw-config', 'config_general_info', '', 45);
    add_submenu_page( 'mdw-config', 'General info', 'Info', 'manage_options', 'mdw-config', 'config_general_info');
    add_submenu_page( 'mdw-config', 'Google Analytics Integration', 'Google Analytics', 'manage_options', 'ga-integration', 'config_ga_integration');

What you have to do is simply overwrite the name of your first submenu page by assigning it to the same menu-slug but with different name.