platform/x86: classmate: mark SPI related data as maybe unused

platform/x86: classmate: mark SPI related data as maybe unused

The driver can be compile tested as built-in making certain data unused:

  drivers/platform/x86/classmate-laptop.c:1137:36: error: ‘cmpc_device_ids’ defined but not used [-Werror=unused-const-variable=]

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230312132624.352703-2-krzysztof.kozlowski@linaro.org
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>