nvmem: bcm-ocotp: mark ACPI device ID table as maybe unused

"bcm_otpc_acpi_ids" is used with ACPI_PTR, so a build with !CONFIG_ACPI
has a warning:

  drivers/nvmem/bcm-ocotp.c:247:36: error:
    ‘bcm_otpc_acpi_ids’ defined but not used [-Werror=unused-const-variable=]

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20220321110326.44652-1-krzk@kernel.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>