cpufreq: CPPC: put ACPI table after using it

Put the ACPI table to release the table mapping after using it
successfully.

Signed-off-by: Hanjun Guo <guohanjun@huawei.com>
[ rjw: Subject & changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>