scsi: NCR5380: Suppress SDTR and WDTR message logging

The 5380 drivers only support asynchronous transfers and the 5380
controllers only have narrow busses. Hence, the core driver will reject
any SDTR and WDTR messages from target devices. Don't log this, it's
expected behaviour. Also, fix the off-by-one array indices in the
arguments to scmd_printk().

Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>