platform/x86: think-lmi: Update password fields to use BIT

Code clean up to use BIT macro as suggested.

Signed-off-by: Mark Pearson <mpearson-lenovo@squebb.ca>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20230601200552.4396-5-mpearson-lenovo@squebb.ca


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