Classical musician wanting to go into contemporary music (Berklee)?

Berklee is not a genre-specific school, there are lots of students who are all or mostly classically trained before coming to Berklee. Especially considering that you have an interest in film scoring, your classical background will be seen as a positive thing. For your audition, your prepared piece can be in whatever style you are most comfortable playing. Jazz/pop knowledge will help you for the sight-reading and improv sections, but a classical piece is fine.