AFAIK, "Stark" is a fairly common last name (one of my sisters has that last name), meaning "Strong" at least in Sweden and probably the neighbor-countries too.
It's not just "Stark", it's "Stark Industries". That is not a coincidence.
Ah, yeah, if it's identical it's probably too much for a coincidence, I'm not too familiar with comics, didn't realize the full name matched. Replied mostly to the "they use the name of an American super hero" part and thought just "Stark" was a superhero but seems I was wrong :)
Iron Man is the superhero persona of Anthony Edward "Tony" Stark, a businessman and engineer who runs the weapons manufacturing company Stark Industries.