scsi: don't add scsi command result bytes

Some drivers are ADDing the scsi command's result bytes instead of ORing
them.

While this can produce correct results it has unexpected side effects.

Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/imm.c

@@ -892,7 +892,7 @@ static int imm_engine(imm_struct *dev, struct scsi_cmnd *cmd)
 			/* Check for optional message byte */
 			if (imm_wait(dev) == (unsigned char) 0xb8)
 				imm_in(dev, &h, 1);
-			cmd->result = (DID_OK << 16) + (l & STATUS_MASK);
+			cmd->result = (DID_OK << 16) | (l & STATUS_MASK);
 		}
 		if ((dev->mode == IMM_NIBBLE) || (dev->mode == IMM_PS2)) {
 			w_ctr(ppb, 0x4);