After a pair of nondescript seasons with the Chargers, Brandon Gorin landed on the Patriots’ practice squad Sept. 5, 2002. This season, Gorin stepped in for the injured Tom Ashworth Nov. 7 in St. Louis, and the Patriots line hasn’t missed a beat. Heading into the playoffs, Gorin said his goal was simple: ‘‘Every game, I know I can do better,’’ he said. With another Super Bowl ring on order, consider it a goal accomplished.