ACPICA: Use ACPI_FALLTHROUGH

ACPICA commit 2296edd39b4ce2d2dd691c1f309c4da00843ecc9

Replace /* FALLTHROUGH */ comment with ACPI_FALLTHROUGH

Link: https://github.com/acpica/acpica/commit/2296edd3


Signed-off-by: Wei Ming Chen <jj251510319013@gmail.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Erik Kaneda <erik.kaneda@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>