sky2: skb recycling

This patch implements skb recycling. It reclaims transmitted skb's
for use in the receive ring.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/sky2.h b/drivers/net/sky2.h
index 92fb24b..b5549c9 100644
--- a/drivers/net/sky2.h
+++ b/drivers/net/sky2.h
@@ -2028,6 +2028,7 @@
 	u16		     rx_pending;
 	u16		     rx_data_size;
 	u16		     rx_nfrags;
+	struct sk_buff_head  rx_recycle;
 
 #ifdef SKY2_VLAN_TAG_USED
 	u16		     rx_tag;