cpufreq: mt8173: add CPUFREQ_HAVE_GOVERNOR_PER_POLICY flag

Add CPUFREQ_HAVE_GOVERNOR_PER_POLICY to have individual set of tunables
for each cluster of MT8173.

Signed-off-by: Pi-Cheng Chen <pi-cheng.chen@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>