platform/x86: thinkpad_acpi: Replace custom str_on_off() etc

Replace enabled(), onoff() and other similar places by str_*() helpers.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220616224951.66660-2-andriy.shevchenko@linux.intel.com


Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>