cpufreq: eff: Introduce Exynos FF.

cpufreq: eff: Introduce Exynos FF.

Change-Id: Ic26f61d8776f2d2420ed279449f017c2074145ef

[9820] cpufreq: eff: get target function using cpufreq ready callback

Change-Id: I54615aea3d248d584490271a0c30a66f42a2ba00

[9820] cpufreq: eff: make filtering condition more precisely

Filtering conditions
  1) SW request (normal request)
    turbo boost is already activated (cur_freq >= boost_threshold)
    and
    this request could activate turbo boost (req_freq >= boost_threshold)

  2) HWI request
    turbo boost is released (cur_freq < boost_threshold)

Change-Id: I5fc21741706de0c0f26d9b4a15c1e8bcad0d1bd6

[9820] cpufreq: eff: clamp frequency SW requests above boost threshold

In case of normal DVFS request (not HWI request),
clamp target value to boost threshold,
if target value > boost threshold.

SW must not request DVFS with frequency above boost threshold.

Change-Id: Ie2cb26e75d2d172f3cfbe02c0a95ca5eb7700c83