Marvin Lewis on Hard Knocks: “No matter what you do there’s a camera there”

Twice before, Bengals coach Marvin Lewis has gotten a first-hand look at HBO’s Hard Knocks.  And he doesn’t sound particularly interested in doing it for a third time. “We’ve done our time for the NFL right now,” Lewis recently told ESPN 101 in St. Louis, via SportsRadioInterviews.com. “I think it’s a great thing for your…