[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: Geert Uytterhoeven <[e-mail]>
Signed-off-by: James Bottomley <[e-mail]>

drivers/scsi/sun3_NCR5380.c

···
     local_irq_restore(flags);
 
     /* Wait for arbitration logic to complete */
-#if NCR_TIMEOUT
+#ifdef NCR_TIMEOUT
     {
       unsigned long timeout = jiffies + 2*NCR_TIMEOUT;