April 21 (Reuters) - Churchill Downs Incorporated announced on Tuesday that it had entered into a definitive agreement to acquire the intellectual property of the Preakness Stakes and Black-Eyed Susan Stakes from 1/ST Racing for $85 million in a deal that unites the first two legs of U.S. thoroughbred racing's Triple Crown.The parties expect the transaction, which is subject to customary conditions, to close after the running of the May 16 Preakness Stakes at Laurel Park in Laurel, Maryland.Churchill Downs, ...