Regina King (“Ray”) is joining the cast of Fox’s “24,” while D.B. Woodside is being bumped up to series regular.In a Kennedyesque twist, Woodside — who plays Wayne Palmer, brother of assassinated President David Palmer — will begin season six as the newly elected president of the United States. “He’ll be RFK to David Palmer’s JFK,” said one person familiar with the storyline. King, meanwhile, joins as heretofore unseen Palmer sister Angela, a powerful lawyer with an advocacy group. From Imagine Television and 20th Century Fox TV, “24” begins its sixth season in January.