Description of problem: This dependency pulls in device-mapper for any packages linking to the device mapper libs. According to the changelog, this was done because of udev rules, but the rules as in device-mapper, so the dependency is not necessary. Version-Release number of selected component (if applicable): device-mapper-1.02.102-2.fc23.x86_64
This is still all correct as far as I can see. If you are using udev on your system, core libdevmapper functionality relies upon those udev rules e.g. to create new device nodes in /dev. The udev rules in turn use dmsetup. The libs got separated into a different package because of multilib.