cpufreq: create cpufreq_generic_init() routine

Many CPUFreq drivers for SMP system (where all cores share same clock lines), do
similar stuff in their ->init() part.

This patch creates a generic routine in cpufreq core which can be used by these
so that we can remove some redundant code.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --cc drivers/cpufreq/Kconfig
Simple merge

diff --cc drivers/cpufreq/cpufreq.c
Simple merge

diff --cc include/linux/cpufreq.h
Simple merge