Nov 15 (Reuters) - Warren Buffett’s Berkshire Hathaway Inc said on Monday it eliminated its investment in Merck & Co and reduced its stakes in Abbvie Inc and Bristol-Myers Squibb Co, as it pared its overall stock market investments. The changes were disclosed in a regulatory filing detailing Berkshire’s U.S.-listed holdings as of Sept. 30. Berkshire also disclosed new investments in Royalty Pharma Plc, which buys pharmaceutical royalties, and flooring retailer Floor & Decor Holdings Inc. Reporting by Jonathan Stempel in New York Editing by Chris Reese