cpufreq: add 'freq_table' in struct cpufreq_policy

freq table is not per CPU but per policy, so it makes more sense to
keep it within struct cpufreq_policy instead of a per-cpu variable.

This patch does it. Over that, there is no need to set policy->freq_table
to NULL in ->exit(), as policy structure is going to be freed soon.

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

drivers/cpufreq/powernow-k6.c

@@ -231,7 +231,6 @@ static int powernow_k6_cpu_exit(struct cpufreq_policy *policy)
 		if (i == max_multiplier)
 			powernow_k6_target(policy, i);
 	}
-	cpufreq_frequency_table_put_attr(policy->cpu);
 	return 0;
 }