By Tzvi Machlin ESPN analyst Robert Griffin III still believes in the Dallas Cowboys despite their stunning loss to the Miami Dolphins over the weekend. He believes there’s one thing they need to win a Super Bowl this year. On today’s edition of Get Up, the former NFL quarterback said that the one thing they need to change is their “mindset.” He said that the team already has the right coaches, players and scheme in place. The thing that they need to show on the field is that they have “guts.” “This @dallascowboys team can win the Super Bowl if they change their mindset. It’s not about personn…