atari_scsi: Remove header

The #defines in atari_scsi.h are intended to influence subsequent #includes
in atari_scsi.c. IMHO, that's too convoluted.

Remove atari_scsi.h by moving those macro definitions to atari_scsi.c,
consistent with other NCR5380 drivers.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>