Apple’s Maps application in iOS 6 will offer users the ability to check-in to Yelp directly from the app, according to a new report. Citing materials Apple distributed to software developers, Bloomberg reports that the integration—which will let users communicate with Yelp without exiting the map—may help Yelp challenge competing check-in services from Foursquare and Facebook. Apple already has a relationship with Yelp through Siri,…