William Christopher, who played the unassuming U.S. Army chaplain, Father Mulcahy, struggling to bring spiritual comfort to an anarchic surgical unit during the Korean War on the long-running hit TV series “M*A*S*H,” died on Saturday. He was 84. Christopher, who was diagnosed with cancer about 18 months ago, died in his bed at his home in Pasadena, California, according to his longtime New York-based agent, Robert Malcolm.