cpufreq: ppc-corenet: remove duplicate update of cpu_data

'cpu_data' is updated for policy->cpu first and then for all CPUs in
policy->cpus. policy->cpus is guaranteed to contain policy->cpu as well and so
the first write to 'cpu_data' for policy->cpu is redundant. Remove it.

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