platform/x86: int3472/discrete: Drop unnecessary obj->type == string check

acpi_evaluate_dsm_typed() already verifies the type is the requested type,
so this error check is a no-op, drop it.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20230204110223.54625-1-hdegoede@redhat.com