Bravo’s “Top Chef” delivered season highs in all demos for its finale Wednesday night as Michael Voltaggio took home the crown.Last episode of Las Vegas-centric season six delivered 3.4 million viewers, up 16% vs. last week. Finale drew nearly 1 million more than the season opener on Aug. 19. Number was down, however, from the season-five finale that drew 3.7 million. Tom Colicchio, Gail Simmons and Toby Young are judges. Padma Lakshmi is host. Production for the seventh season will begin in January.