The drugmaker Allergan announced Friday that it had transferred its patents on a best-selling eye drug to the Saint Regis Mohawk Tribe in upstate New York, an unusual gambit to protect the drug from a patent dispute. Under the deal, which involves the dry-eye drug Restasis, Allergan will pay the tribe $13.75 million. In exchange, the tribe will claim sovereign immunity as grounds to dismiss a patent challenge through a unit of the United States Patent and Trademark Office. Th