cpufreq: powerpc: move cpufreq driver to drivers/cpufreq

Move cpufreq driver of powerpc platform to drivers/cpufreq.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Merge branch 'pm-cpufreq-next' into bleeding-edge

* pm-cpufreq-next:
  cpufreq: powerpc: move cpufreq driver to drivers/cpufreq
  cpufreq: kirkwood: Select CPU_FREQ_TABLE option
  cpufreq: big.LITTLE needs cpufreq table
  cpufreq: SPEAr needs cpufreq table