scsi: core: Drop the now obsolete driver_byte definitions

The driver_byte field in the result is now unused, so we can drop the
definitions.

Link: https://lore.kernel.org/r/20210427083046.31620-15-hare@suse.de


Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>