* US Justice Dept, N.Y. DA's Office announce settlement * Comes in addition to $340 mln paid to N.Y. bank regulator * HSBC settlement of similar allegations expected soon By Aruna Viswanatha WASHINGTON, Dec 10 (Reuters) - Standard Chartered Plc agreed to pay $327 million to resolve allegations that it violated U.S. sanctions against Iran, Sudan and two other countries, capping months of legal headaches for the British bank. The U.S. Justice Department and the New York Dis