scsi: aic7xxx: aic79xx: Drop internal SCSI message definition

Use the standard SCSI message definitions instead of the driver-internal
ones.

Link: https://lore.kernel.org/r/20210113090500.129644-20-hare@suse.de
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>