cpufreq-dt: pass 'policy->related_cpus' to of_cpufreq_cooling_register()

The second parameter of of_cpufreq_cooling_register() should be the CPUs to
which the frequency constraint will apply. As the cpufreq-dt driver now supports
platforms with multiple 'struct cpufreq_policy' instances (i.e. > 1 clock
domains for CPUs), passing 'cpu_present_mask' isn't correct anymore. As every
policy will have a set of CPUs and that may not be equal to 'cpu_present_mask'
always.

So, pass only mask of CPUs which are controlled by current policy.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Eduardo Valentin <edubezval@gmail.com>
Tested-by: Eduardo Valentin <edubezval@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>