[SCSI] sun3: Check for NCR_TIMEOUT being defined instead of having a value

This fixes:

drivers/scsi/sun3_NCR5380.c:1448:5: warning: "NCR_TIMEOUT" is not defined
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

drivers/scsi/sun3_NCR5380.c

@@ -1445,7 +1445,7 @@ static int NCR5380_select(struct Scsi_Host *instance, struct scsi_cmnd *cmd,
     local_irq_restore(flags);
 
     /* Wait for arbitration logic to complete */
-#if NCR_TIMEOUT
+#ifdef NCR_TIMEOUT
     {
       unsigned long timeout = jiffies + 2*NCR_TIMEOUT;