ASIA MINOR: Longtime journalist and author Stanley Karnow, an Asia specialist, writes in this month's Smithsonian magazine that visiting Orange County's Little Saigon area was \o7 deja vu\f7 for him: "When I left Vietnam I never expected to see Saigon again. But I am back there now, at least in spirit . . . a facsimile Saigon in Orange County." Karnow also notes that officials gave it a freeway sign "in hopes of diverting tourists from nearby Disneyland."