cpufreq: freq_table: Demote obvious misuse of kerneldoc to standard comment blocks

No attempt has been made to document any of the demoted functions here.

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

 drivers/cpufreq/freq_table.c:229: warning: Function parameter or member 'policy' not described in 'show_available_freqs'
 drivers/cpufreq/freq_table.c:229: warning: Function parameter or member 'buf' not described in 'show_available_freqs'
 drivers/cpufreq/freq_table.c:229: warning: Function parameter or member 'show_boost' not described in 'show_available_freqs'
 drivers/cpufreq/freq_table.c:269: warning: Function parameter or member 'policy' not described in 'scaling_available_frequencies_show'
 drivers/cpufreq/freq_table.c:269: warning: Function parameter or member 'buf' not described in 'scaling_available_frequencies_show'
 drivers/cpufreq/freq_table.c:281: warning: Function parameter or member 'policy' not described in 'scaling_boost_frequencies_show'
 drivers/cpufreq/freq_table.c:281: warning: Function parameter or member 'buf' not described in 'scaling_boost_frequencies_show'

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>