I have a Lenovo Thinkpad T440s, and everything is working pretty much out-of-the-box on Fedora 25, except for the fingerprint scanner. It is detected automatically, and flashes when necessary, and seems to "work", however it never matches my fingerprint (it always says that it is not a match). Is there anything I could try? I also saw that this scanner (by Validity) is not officially supported by fprint.
The current release of libfprint(0.6.0) is not working great with the sensors used in recent Lenovo. On my T550, it only ask me to swipe once when enrolling a finger and then fail to recognize it 9/10 times.
If I'm updating to the version in git HEAD it asks me to swipe my finger 5 times and then the recognition is working way better.
So you should probably try to compile the git HEAD yourself and try again.
I would also suggest you to open a bug on the Fedora bugtracker.