ucc_geth: Add support for skb recycling

We can reclaim transmitted skbs to use in the receive path, so-called
skb recycling support.

Also reorder ucc_geth_poll() steps, so that we'll clean tx ring firstly,
thus maybe reclaim some skbs for rx.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ucc_geth.h b/drivers/net/ucc_geth.h
index 195ab26..cfb31af 100644
--- a/drivers/net/ucc_geth.h
+++ b/drivers/net/ucc_geth.h
@@ -1212,6 +1212,8 @@
 	/* index of the first skb which hasn't been transmitted yet. */
 	u16 skb_dirtytx[NUM_TX_QUEUES];
 
+	struct sk_buff_head rx_recycle;
+
 	struct ugeth_mii_info *mii_info;
 	struct phy_device *phydev;
 	phy_interface_t phy_interface;