net: Increase xmit RECURSION_LIMIT to 10.

Three is definitely too low, and we know from reports that GRE tunnels
stacked as deeply as 37 levels cause stack overflows, so pick some
reasonable value between those two.

Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/dev.c

@@ -2213,7 +2213,7 @@ static inline int __dev_xmit_skb(struct sk_buff *skb, struct Qdisc *q,
 }
 
 static DEFINE_PER_CPU(int, xmit_recursion);
-#define RECURSION_LIMIT 3
+#define RECURSION_LIMIT 10
 
 /**
  *	dev_queue_xmit - transmit a buffer