mac_scsi: Remove header

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

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

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