By Jennifer Piacenti A Bengals-Eagles Super Bowl matchup is the betting favorite at SI Sportsbook, while three Super Bowl outcomes are tied for the best odds. It’s time to start placing your Super Bowl LVII bets, and if you’re already picking a winner in the championship round why not pick two? This weekend, a new AFC and NFC champion will punch their tickets to the big game and SI Sportsbook has odds for the big game’s exact matchup and outcome. There are only four teams left—Chiefs, Bengals, Eagles, 49ers—meaning there are four possible Super Bowl LVII matchups with eight possible outcomes. …