Apple is using a little-known guideline document in an attempt to curb third-party iPad and iPhone giveaways, according to a new report. Fortune claims that Apple has only recently begun to reach out to companies in an attempt to enforce its Guidelines for Third Party Promotions, a document that has been around since at least last January. The rules for third-party promotions forbid the use of the iPad, iPhone, or iPhone Gift Card in a promotion,…