The mobile site is packaged as a portal extension. All the portlets and portal configuration are contained within this extension and it is this extension which creates the mobile site and configures the redirection service for this site. If you do not wish to have the mobile site, the extension can be removed before starting the server.
The extension to remove is located at :
jboss/gatein/extensions/gatein-mobile-integration.ear
To mobile site can also be manually removed by deleting the mobile site and removing the classic site's mobile redirect configuration.