Usher was riding high last night — and it wasn’t just because he nailed the Super Bowl halftime. The Yeah! singer, 45, officially got hitched to his longtime girlfriend, Jennifer Goicoechea, in Las Vegas on Sunday, and his mother, Jonnetta Patton, served as the newlywed’s witness, RadarOnline.com has learned. The new Mr. and Mrs. Raymond said “I do” at Vegas Weddings. Usher’s top-secret ceremony was officiated byRev. Ronald Joseph Pokrywka on the same day as the performer’s Super Bowl halftime show. Usher and Jennifer’s hush-hush nuptials were laid bare in their marriage certificate obtained b…