CHICAGO, Dec 13 - Philip Morris USA said on Wednesday it was raising prices on all its cigarette brands by 10 cents per pack as of Dec. 18, a move that had been expected by analysts.The price increase was accomplished by lowering promotional discounts the company offers on its Marlboro, Virginia Slims, Parliament and Basic brands, while raising list prices on other brands, a spokesman for the unit of Altria Group Inc. <MO.N> said.Since changes in promotional discounts are typically passed on to consumers, the move could raise the average price a smoker pays for a pack of top-selling Marlboro...