scsi: target: Make the virtual LUN 0 device

Create the device for the virtual LUN 0 using the DUMMY flag. This change
makes it possible to remove some special-casing in the INQUIRY code.

Link: https://lore.kernel.org/r/20210322200938.53300-3-k.shelekhin@yadro.com


Reviewed-by: Roman Bolshakov <r.bolshakov@yadro.com>
Reviewed-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Konstantin Shelekhin <k.shelekhin@yadro.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>