platform/x86: serial-multi-instantiate: Drop duplicate check

The device_get_match_data() checks for firmware node to be present,
there is no need to check for ACPI companion.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220709211653.18938-2-andriy.shevchenko@linux.intel.com


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