cpufreq: Fix parameter in parse_perf_domain()

Pass cpu to parse_perf_domain() instead of pcpu.

Fixes: 8486a32d ("cpufreq: Add of_perf_domain_get_sharing_cpumask")
Signed-off-by: Hector.Yuan <hector.yuan@mediatek.com>
[ Viresh: Massaged changelog ]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>