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 <[e-mail]>
Acked-by: Viresh Kumar <[e-mail]>
Signed-off-by: Rafael J. Wysocki <[e-mail]>

drivers/cpufreq/cpufreq_governor.c

···
 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