platform/x86: think-lmi: Correct System password interface

platform/x86: think-lmi: Correct System password interface

The system password identification was incorrect. This means that if
the password was enabled it wouldn't be detected correctly; and setting
it would not work.
Also updated code to use TLMI_SMP_PWD instead of TLMI_SYS_PWD to be in
sync with Lenovo documentation.

Fixes: 640a5fa50a42 ("platform/x86: think-lmi: Opcode support")
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/20230601200552.4396-3-mpearson-lenovo@squebb.ca
Signed-off-by: Hans de Goede <hdegoede@redhat.com>