cpufreq: check only freq_table in __resolve_freq()

There is no need to check if the cpufreq driver implements callback
cpufreq_driver::target_index. The logic in the __resolve_freq uses
the frequency table available in the policy. It doesn't matter if the
driver provides 'target_index' or 'target' callback. It just has to
populate the 'policy->freq_table'.

Thus, check only frequency table during the frequency resolving call.

Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>