net: Fix duplicate volatile warning.

jiffies is defined as "volatile".

  extern unsigned long volatile __jiffy_data jiffies;

ACCESS_ONCE() uses "volatile".
As a result, some compilers warn duplicate `volatile' for ACCESS_ONCE(jiffies).
Signed-off-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/net/neighbour.h

@@ -303,7 +303,7 @@ static inline void neigh_confirm(struct neighbour *neigh)
 
 static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
 {
-	unsigned long now = ACCESS_ONCE(jiffies);
+	unsigned long now = jiffies;
 	
 	if (neigh->used != now)
 		neigh->used = now;