By Alek Arend NFL quarterback Baker Mayfield has finally been traded. The Carolina Panthers – who’ve been linked to Mayfield all offseason – acquired Mayfield from the Cleveland Browns on Wednesday. All they had to give up was a fifth-round pick. Mayfield now enters a quarterback room featuring Sam Darnold and third-round draft pick Matt Corral. Robert Griffin III thinks the Panthers’ quarterback competition is going to be closer than people expect. “The @Panthers have quietly improved their offensive line drastically, have dynamic starters at the offensive skill positions and a budding defens…