RDMA/cxgb3: Don't free skbs on NET_XMIT_* indications from LLD

The low level cxgb3 driver can return NET_XMIT_CN and friends.
The iw_cxgb3 driver should _not_ treat these as errors.
Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/hw/cxgb3/iwch_cm.c

@@ -151,7 +151,7 @@ int iwch_l2t_send(struct t3cdev *tdev, struct sk_buff *skb, struct l2t_entry *l2
 		return -EIO;
 	}
 	error = l2t_send(tdev, skb, l2e);
-	if (error)
+	if (error < 0)
 		kfree_skb(skb);
 	return error;
 }
@@ -167,7 +167,7 @@ int iwch_cxgb3_ofld_send(struct t3cdev *tdev, struct sk_buff *skb)
 		return -EIO;
 	}
 	error = cxgb3_ofld_send(tdev, skb);
-	if (error)
+	if (error < 0)
 		kfree_skb(skb);
 	return error;
 }