an entrepreneur needs a good foundation in business, so definitely take some accounting classes. marketing seems like another useful area to be familiar with.
a big piece of entrepreneurship is bringing together a group of people to accomplish something. soft skills are key here. management, communications, psychology should be helpful.
as the world is becoming more and more driven by technology, majors like computer science & engineering can endow one with a very useful array of skills. integrating physics, biology, data or neuroscience has much promise
finally, consider what you really like or are curious about, that might lead you towards your major field of study