Introduce CPUFREQ_RELATION_C

It selects the frequency with the minimum euclidean distance to
target. In case of equal distance between 2 frequencies, it will
select the greater freq.

Created by Stratos Karafotis <stratosk@semaphore.gr>

Original commit: https://github.com/XileForce/Vindicator-S6/commit/4b113d38e8f62ea5810d2b4d134cc6f7a81198dd