ACPI: Use str_low_high() helper in two places

Replace hard-coded string choices with the str_low_high() helper
in two places in the ACPI code.

Signed-off-by: Chelsy Ratnawat <chelsyratnawat2001@gmail.com>
Link: https://patch.msgid.link/20250823220311.2035533-1-chelsyratnawat2001@gmail.com


[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>