Revert "cache-l2x0.c/cache-l2x0.h: Revert 3.0.92 changes"

This reverts commit 243d6ddee8027e2918bfa31a3aa467acd4399070.
arch/arm/mm/cache-l2x0.c: Fix for linux 3.0.92
Version 0.7b - compatibility improved and forgotten things
Changelog:

        - fixed stuck at max scaling frequency when using stock kernel sources with unmodified cpufreq driver and without any oc capabilities.
        - readded forgotten frequency search optimisation in scaling logic (only effective when using governor soft frequency limit)
        - readded forgotten minor optimisation in dbs_check_cpu function
        - as forgotten to switch in last version Legacy Mode now again disabled by default
        - minor code format and comment fixes