Yum Brands, whose restaurants have been selling crispy chicken in Beijing since 1987, is separating its China business from its U.S. operations after pressure from an activist investor.Yum China will become a franchisee of Yum in the Asian country, with exclusive rights to KFC, Pizza Hut and Taco Bell, according to a statement Tuesday.The move follows calls from hedge fund manager Keith Meister, a protege of billionaire Carl Icahn, who has said Yum's Asian market could be better served with a more focused business and that the move could boost Yum's value by $7 billion. The fast-food giant added Meister,...