cpufreq: stats: Clean up local variable in cpufreq_stats_create_table()

Local variable 'count' will be initialized and 'ret' is also not
required, so remove the redundant initialization and get rid of
'ret'.

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