cppc_acpi: add acpi_cpc_valid for determining _CPC is valid

kunpeng inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I7C2TX


CVE: NA

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Add acpi_cpc_valid for determining _CPC is valid.

Signed-off-by: Jie Liu <liujie375@h-partners.com>