cpufreq: governor: Remove fossil comment in the cpufreq_governor_dbs()

The related code has been changed and the comment is out of date.
So remove it.

Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>