r8169: Revert BQL and xmit_more support.

There are certain regressions which are pointing to
these two commits which we are having a hard time
resolving.  So revert them for now.

Specifically this reverts:

	commit 0bec3b70
	Author: Florian Westphal <fw@strlen.de>
	Date:   Wed Jan 7 10:49:49 2015 +0100

	    r8169: add support for xmit_more

and

	commit 1e918876
	Author: Florian Westphal <fw@strlen.de>
	Date:   Wed Oct 1 13:38:03 2014 +0200

	    r8169: add support for Byte Queue Limits

There were some attempts by Eric Dumazet to address some obvious
problems in the TX flow, to see if they would fix the problems,
but none of them seem to help for the regression reporters.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/realtek/r8169.c

@@ -5067,8 +5067,6 @@ static void rtl_hw_reset(struct rtl8169_private *tp)
 	RTL_W8(ChipCmd, CmdReset);
 
 	rtl_udelay_loop_wait_low(tp, &rtl_chipcmd_cond, 100, 100);
-
-	netdev_reset_queue(tp->dev);
 }
 
 static void rtl_request_uncached_firmware(struct rtl8169_private *tp)
@@ -7049,7 +7047,6 @@ static netdev_tx_t rtl8169_start_xmit(struct sk_buff *skb,
 	u32 status, len;
 	u32 opts[2];
 	int frags;
-	bool stop_queue;
 
 	if (unlikely(!TX_FRAGS_READY_FOR(tp, skb_shinfo(skb)->nr_frags))) {
 		netif_err(tp, drv, dev, "BUG! Tx Ring full when queue awake!\n");
@@ -7090,8 +7087,6 @@ static netdev_tx_t rtl8169_start_xmit(struct sk_buff *skb,
 
 	txd->opts2 = cpu_to_le32(opts[1]);
 
-	netdev_sent_queue(dev, skb->len);
-
 	skb_tx_timestamp(skb);
 
 	/* Force memory writes to complete before releasing descriptor */
@@ -7106,16 +7101,11 @@ static netdev_tx_t rtl8169_start_xmit(struct sk_buff *skb,
 
 	tp->cur_tx += frags + 1;
 
-	stop_queue = !TX_FRAGS_READY_FOR(tp, MAX_SKB_FRAGS);
+	RTL_W8(TxPoll, NPQ);
 
-	if (!skb->xmit_more || stop_queue ||
-	    netif_xmit_stopped(netdev_get_tx_queue(dev, 0))) {
-		RTL_W8(TxPoll, NPQ);
-
-		mmiowb();
-	}
+	mmiowb();
 
-	if (stop_queue) {
+	if (!TX_FRAGS_READY_FOR(tp, MAX_SKB_FRAGS)) {
 		/* Avoid wrongly optimistic queue wake-up: rtl_tx thread must
 		 * not miss a ring update when it notices a stopped queue.
 		 */
@@ -7198,7 +7188,6 @@ static void rtl8169_pcierr_interrupt(struct net_device *dev)
 static void rtl_tx(struct net_device *dev, struct rtl8169_private *tp)
 {
 	unsigned int dirty_tx, tx_left;
-	unsigned int bytes_compl = 0, pkts_compl = 0;
 
 	dirty_tx = tp->dirty_tx;
 	smp_rmb();
@@ -7222,8 +7211,10 @@ static void rtl_tx(struct net_device *dev, struct rtl8169_private *tp)
 		rtl8169_unmap_tx_skb(&tp->pci_dev->dev, tx_skb,
 				     tp->TxDescArray + entry);
 		if (status & LastFrag) {
-			pkts_compl++;
-			bytes_compl += tx_skb->skb->len;
+			u64_stats_update_begin(&tp->tx_stats.syncp);
+			tp->tx_stats.packets++;
+			tp->tx_stats.bytes += tx_skb->skb->len;
+			u64_stats_update_end(&tp->tx_stats.syncp);
 			dev_kfree_skb_any(tx_skb->skb);
 			tx_skb->skb = NULL;
 		}
@@ -7232,13 +7223,6 @@ static void rtl_tx(struct net_device *dev, struct rtl8169_private *tp)
 	}
 
 	if (tp->dirty_tx != dirty_tx) {
-		netdev_completed_queue(tp->dev, pkts_compl, bytes_compl);
-
-		u64_stats_update_begin(&tp->tx_stats.syncp);
-		tp->tx_stats.packets += pkts_compl;
-		tp->tx_stats.bytes += bytes_compl;
-		u64_stats_update_end(&tp->tx_stats.syncp);
-
 		tp->dirty_tx = dirty_tx;
 		/* Sync with rtl8169_start_xmit:
 		 * - publish dirty_tx ring index (write barrier)