cpufreq: Pass policy to cpufreq_add_policy_cpu()

The caller of cpufreq_add_policy_cpu() already has a pointer to the
policy structure and there is no need to look it up again in
cpufreq_add_policy_cpu().  Let's pass it directly.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>