atm: use msecs_to_jiffies for conversions

API compliance scanning with coccinelle flagged:
./drivers/atm/iphase.c:2621:4-20:
        WARNING: timeout (50) seems HZ dependent

Numeric constants passed to schedule_timeout() make the effective
timeout HZ dependent which does not seem intended.
Fixed up by converting the constant to jiffies with msecs_to_jiffies()
As this driver was introduced in the early 2.3 series it is most
likely assuming HZ=100 so the constant 50 is converted to 500ms.
Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/atm/iphase.c

@@ -2618,7 +2618,7 @@ static void ia_close(struct atm_vcc *vcc)
         if (vcc->qos.txtp.traffic_class != ATM_NONE) {
            iadev->close_pending++;
 	   prepare_to_wait(&iadev->timeout_wait, &wait, TASK_UNINTERRUPTIBLE);
-	   schedule_timeout(50);
+	   schedule_timeout(msecs_to_jiffies(500));
 	   finish_wait(&iadev->timeout_wait, &wait);
            spin_lock_irqsave(&iadev->tx_lock, flags); 
            while((skb = skb_dequeue(&iadev->tx_backlog))) {