platform/x86: simatic-ipc: add another model BX-21A

This adds support for the Siemens Simatic IPC model BX-21A. Actual
drivers for that model will be sent in separate patches.

Signed-off-by: Henning Schild <henning.schild@siemens.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230713115639.16419-2-henning.schild@siemens.com


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