scsi: aic7xxx: aic79xx: Kill pointless forward declarations

Link: https://lore.kernel.org/r/20210113090500.129644-8-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>