Master P says he earned an NBA contract with 2 different teams in the ’90s — after he was already a famous rap mogul — and he knows what it takes to get to the top level. P — whose music and hoops careers are documented in BET’s “No Limit Chronicles” — tells TMZ Sports he had a lengthy conversation with J. Cole about his hoop dreams … and says he’s convinced the rapper is dead serious. “When I talked to J. Cole, he was like ‘You know, big dog you did it. What do you think I would have to do to make it happen?’”