By Marina Lopes WASHINGTON (Reuters) – ATT Incs second-quarter revenue rose, but slightly less than Wall Street forecasts, as a promotional offer to charge customers for devices separately from service weighed on average revenue per user. The No. 2 U.S. mobile provider said on Wednesday that, excluding items, it earned 62 cents, one penny less than Wall Street expectations according to Thomson Reuters I/B/E/S. ATT shares fell 1.67 percent to $35.28 after closing at $35.88 on the New York Stock Exchange. …