Miroslav,
Sorry for the delayed response. It's pretty easy to add the drop-down fields to the Profiles area of JLinked so that you can map LinkedIn fields to CB. However, the problem with that is that LinkedIn's "Industry" values likely don't align with what you have as options in Community Builder. If you import values from LinkedIn into CB that aren't available as options in CB, I don't know how CB will handle that.
That's the reason we currently only support text fields and a few other specific input type values (like birthday). For Industry, on LinkedIn, I believe a user can enter any value they want, which could be a problem.
If you'd like us to help show you how to import into a select field on CB, we'll gladly do so. You'll just need to test to ensure things work how you want/expect them too.
Thanks,
Alex