Walter Royal, the chef of a destination steakhouse in North Carolina who triumphed as a challenger on “Iron Chef America” by cooking mostly Southern dishes with ostrich meat, has died. The Angus Barn in Raleigh, where Royal served as executive chef since the 1990s, announced his passing on its website. Royal was already well established as a chef in the Raleigh area when he cooked before a national audience in a 2006 episode of “Iron Chef America.”