Robert Maxwell said he is giving up his bid for Bell & Howell Co., seemingly clearing the way for BHW Acquisition, comprised of Robert M. Bass Group and some top Bell & Howell managers, to take over the U.S. information-services concern. Maxwell Communication had expressed an interest in Skokie, Ill.-based Bell & Howell before the Bass group made a bid. "One of the two firms has decided not to go any further forward," Maxwell said in reply to a question at a news conference in West Germany coinciding with his company's listing on the Frankfurt Stock Exchange. He said this meant that Maxwell Communication was not pursuing its bid for Bell & Howell. As of last Thursday, Maxwell held 2.3% of the company, formerly known for its home movie cameras and slide projectors.