ACPICA: Add "root node" case to the ACPI name repair code

ACPICA commit 95b40b31aa8148629fbe5de0356725fc01298003

Special-case the namespace root node, it has an unusual name.

This case can occur if there are errors during the execution
of module-level code.

Link: https://github.com/acpica/acpica/commit/95b40b31


Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>