ACPICA commit 0ebacf12b8ca66ce6d3fce4d349b3f2448da18cb

A linux-based static analyzer (sparse) caught this as a warning.
Making this variable static will result in better optimizations and
ensure that this variable does not get used outside of this file.
Signed-off-by: Yue Haibing <yuehaibing@huawei.com>
[ek: commit message]

Link: https://github.com/acpica/acpica/commit/0ebacf12Signed-off-by: Erik Kaneda <erik.kaneda@intel.com>
Signed-off-by: Yue Haibing <yuehaibing@huawei.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>