net: convert remaining non-symbolic return values in ndo_start_xmit() functions

This patch converts the remaining occurences of raw return values to their
symbolic counterparts in ndo_start_xmit() functions that were missed by the
previous automatic conversion.

Additionally code that assumed the symbolic value of NETDEV_TX_OK to be zero
is changed to explicitly use NETDEV_TX_OK.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index d238a89..2ffb35d 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -1627,7 +1627,7 @@
 	u32 sta_flags = 0;
 
 	if (unlikely(skb->len < ETH_HLEN)) {
-		ret = 0;
+		ret = NETDEV_TX_OK;
 		goto fail;
 	}
 
@@ -1664,7 +1664,7 @@
 		if (!sdata->u.mesh.mshcfg.dot11MeshTTL) {
 			/* Do not send frames with mesh_ttl == 0 */
 			sdata->u.mesh.mshstats.dropped_frames_ttl++;
-			ret = 0;
+			ret = NETDEV_TX_OK;
 			goto fail;
 		}
 		memset(&mesh_hdr, 0, sizeof(mesh_hdr));
@@ -1724,7 +1724,7 @@
 		hdrlen = 24;
 		break;
 	default:
-		ret = 0;
+		ret = NETDEV_TX_OK;
 		goto fail;
 	}
 
@@ -1766,7 +1766,7 @@
 
 		I802_DEBUG_INC(local->tx_handlers_drop_unauth_port);
 
-		ret = 0;
+		ret = NETDEV_TX_OK;
 		goto fail;
 	}
 
@@ -1858,10 +1858,10 @@
 	dev->trans_start = jiffies;
 	dev_queue_xmit(skb);
 
-	return 0;
+	return NETDEV_TX_OK;
 
  fail:
-	if (!ret)
+	if (ret == NETDEV_TX_OK)
 		dev_kfree_skb(skb);
 
 	return ret;