As a teenager LL COOL J was the first artist signed to the Def Jam label, becoming one of the first major hip-hop stars, with hits like “Going Back to Cali” and “Mama Said Knock You Out.” He turned to acting, starring for 14 seasons on “NCIS: Los Angeles.” Now 56, he’s returned to the thing he loves most – rapping – with his first album in more than a decade, “The FORCE.” He talks with “Sunday Morning” contributor Kelefa Sanneh about the origins of his career, and the magic of making a hip-hop record.