[SUNRPC]: Fix nsec --> usec conversion.

We need to divide, not multiply.  While we're here,
use NSEC_PER_USEC instead of a magic constant.

Based upon a report from Josip Loncaric and a patch
by Andrew Morton.
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sunrpc/svcsock.c

@@ -586,7 +586,7 @@ svc_udp_recvfrom(struct svc_rqst *rqstp)
 	}
 	if (skb->stamp.tv_sec == 0) {
 		skb->stamp.tv_sec = xtime.tv_sec; 
-		skb->stamp.tv_usec = xtime.tv_nsec * 1000; 
+		skb->stamp.tv_usec = xtime.tv_nsec / NSEC_PER_USEC; 
 		/* Don't enable netstamp, sunrpc doesn't 
 		   need that much accuracy */
 	}