WASHINGTON (Reuters) – A U.S. appeals court on Wednesday affirmed a decision by the International Trade Commission that Apple Inc <AAPL.O> was innocent of violating three patents owned by Samsung Electronics <005930.KS> to make its iPhones and iPads. Apple and Samsung have been litigating around the world for three years, each accusing the other of infringing patents in making smartphones and other mobile devices. Neither side has scored a crippling sales ban.