Sylvester Stallone is doing a career retrospective interview with The New York Times as part of a promotional tour for his upcoming memoir, and he’s talked about wanting to be seen as a serious actor, revealing why he gravitated toward making a movie like James Mangold‘s often-overlooked corrupt cop thriller “Cop Land,” where he would gain a bunch of weight and play against type as the soft-spoken small-town sheriff dealing with a group of degen…