Cosa Nostra don Toto Riina has been watching his life story on the tube — from a high-security Milan jail cell.And he’s not the only one watching. Millions of Italian viewers have made the six-part biopic, titled “Capo dei Capi” (Boss of Bosses), Italy’s top-rated drama of the season. It debuted to a stellar 27.8% primetime share on Mediaset’s Canale 5. The series, which realistically chronicles Riina’s rise from lowly shepherd to supreme capo, reps a breakthrough on Italian TV, where the mob has traditionally been depicted mostly by stale stereotypes. Coincidentally, “Capo” was preemed in the Sicilian town of Corleone, which besides its obvious association with “The Godfather” is also Riina’s birthplace and former stomping ground.