cpufreq: cpufreq-cpu0: Free parent node for error cases

We are freeing parent node in success cases but not in failure cases.
Let's do it.

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