scsi: fdomain: drop fdomain_pci_tbl when built-in

The fdomain SCSI host driver is one of the last remaining drivers that
manually search the PCI bus using pci_get_device rather than registering
a pci_driver instance.

This means the module device table is unused when the driver is
built-in, and we get a warning about it:

drivers/scsi/fdomain.c:1773:29: warning: 'fdomain_pci_tbl' defined but not used [-Wunused-variable]

To avoid the warning, this adds another #ifdef around the table
definition.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>