I’m done working for the man, what kind of figurative language is this

Personification

I don't see any non-human involved in that statement.

I see it as a part of a dialect.

It could be considered synecdoche, in which "the man" means "the government." However, whether it's a form of synecdoche depends on the context. One sentence hardly tells us anything.

http://literary-devices.com/content/synecdoche

The phrase "working for the man" is an example of figurative language known as an idiom. An idiom is a commonly used expression that has a meaning different from the literal interpretation of its individual words. In this case, "the man" is not referring to a specific person, but rather symbolizes authority or the oppressive nature of a boss or employer. It signifies the desire to break free from the constraints of a job or the corporate world.