The Bonn government is revving up efforts to open the telecommunications market in eastern Germany. The aim is to bring down prices and improve service. Now, several U.S. companies are bidding on a private cellular-phone license--the country's second--to be awarded by yearend. BellSouth Corp. has already teamed up with Germany's Thyssen and Britain's Vodafone. U.S. West Inc. will also be in the field, which will even include prestige carmaker BMW. Germany's first private mobile-phone consortium, which includes Pacific Telesis Group, will begin operations in March.