cpufreq: simplified goto out in cpufreq_register_driver()

simplified goto out in cpufreq_register_driver for increasing
code readability

Signed-off-by: Pankaj Gupta <pankaj.gupta@spreadtrum.com>
Signed-off-by: Sanjeev Yadav <sanjeev.yadav@spreadtrum.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>