Where did you get the impression that it could be a stereotype, racist or otherwise?
It also depends on what type of dance you have in mind. Jackson may be able to do weird things with his body in time to music (What is it? Breakdancing?), but that's a world away from, say, ballet, tap, Irish or Indian dancing. I wouldn't say there's a predominance of black people in any of those forms.
Like white people, there are black people who are good dancers, there are black people who are bad dancers. I've never heard of them being thought of as better by dint of the fact that they are black.