ACPI: CPPC: Avoid out of bounds access when parsing _CPC data

stable inclusion
from stable-4.19.238
commit 28d5387c1994f5e1e0d41b30a1f3dd6e1f609252
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5A6BA
CVE: NA

--------------------------------

commit 40d8abf3 upstream.

If the NumEntries field in the _CPC return package is less than 2, do
not attempt to access the "Revision" element of that package, because
it may not be present then.

Fixes: 337aadff ("ACPI: Introduce CPU performance controls using CPPC")
BugLink: https://lore.kernel.org/lkml/20220322143534.GC32582@xsang-OptiPlex-9020/


Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com>