NEW YORK (AP) — Robert Downey Jr. set out to make an objective portrait, a tribute to his father, the underground filmmaking maverick Robert Downey Sr. His dad had other plans. The result is “Sr.,” a new Netflix documentary about a father-son relationship that in some ways always existed on camera. Downey Jr. made his movie debut in his father’s 1970 film “The Pound,” at the age of 5. “Sr.” is a son’s loving reckoning with his iconoclast father, a freewheeling cult filmmaker whose experimental films gave Downey Jr. his entry into moviemaking. It debuts Monday on Netflix.