Charmaine Bingwa (“The Good Fight”) and Nkeki Obi-Melekwe (“Tina -The Tina Turner Musical”) have been added to Showtime’s “King Shaka” cast as series regulars, the network announced on Thursday. Tony Kgoroge (“Invictus”), Sindi Dlatu (“The River”) and Bahle Hadebe (“Bone of My Bones”) will guest star in recurring roles. According…