All cpufreq drivers with a freq-table are migrated to use
cpufreq_table_validate_and_show() long back and the routine
cpufreq_frequency_table_cpuinfo() isn't used outside of cpufreq core
now.
Unexport it and update Documentation as well.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>