cpufreq: cpufreq_governor: Demote store_sampling_rate() header to standard comment block

There is no need for this to be denoted as kerneldoc.

Fixes the following W=1 kernel build warning(s):

 drivers/cpufreq/cpufreq_governor.c:46: warning: Function parameter or member 'attr_set' not described in 'store_sampling_rate'
 drivers/cpufreq/cpufreq_governor.c:46: warning: Function parameter or member 'buf' not described in 'store_sampling_rate'
 drivers/cpufreq/cpufreq_governor.c:46: warning: Function parameter or member 'count' not described in 'store_sampling_rate'
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/cpufreq/cpufreq_governor.c

@@ -26,7 +26,7 @@ static DEFINE_PER_CPU(struct cpu_dbs_info, cpu_dbs);
 static DEFINE_MUTEX(gov_dbs_data_mutex);
 
 /* Common sysfs tunables */
-/**
+/*
  * store_sampling_rate - update sampling rate effective immediately if needed.
  *
  * If new rate is smaller than the old, simply updating