Fix memory leak in cpufreq stats.

commit e37736777254ce1abc85493a5cacbefe5983b896 upstream.

When system enters sleep, non-boot CPUs will be disabled.
Cpufreq stats sysfs is created when the CPU is up, but it is not
freed when the CPU is going down. This will cause memory leak.

Signed-off-by: xiaobing tu <xiaobing.tu@intel.com>
Signed-off-by: guifang tang <guifang.tang@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Colin Cross <ccross@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>