cpufreq: schedutil: Merge initialization code of sg_cpu in single loop

The initialization code of the per-cpu sg_cpu struct is currently split
into two for-loop blocks. This can be simplified by merging the two
blocks into a single loop. This will make the code more maintainable.

Signed-off-by: Liao Chang <liaochang1@huawei.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>