cpufreq: ondemand: Remove redundant return statement

After commit dfa5bb62 (cpufreq: ondemand: Change the calculation
of target frequency), this return statement is no longer needed.

Reported-by: Henrik Nilsson <Karl.Henrik.Nilsson@gmail.com>
Signed-off-by: Stratos Karafotis <stratosk@semaphore.gr>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>