net: stmmac: Do not set RX IC bit if RX Coalesce is zero

We may only want to use the RX Watchdog so lets check if RX Coalesce
settings are non-zero and only set the RX Interrupt on Completion bit if
its not.
Signed-off-by: Jose Abreu <Jose.Abreu@synopsys.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

@@ -3440,7 +3440,11 @@ static inline void stmmac_rx_refill(struct stmmac_priv *priv, u32 queue)
 		rx_q->rx_count_frames += priv->rx_coal_frames;
 		if (rx_q->rx_count_frames > priv->rx_coal_frames)
 			rx_q->rx_count_frames = 0;
-		use_rx_wd = priv->use_riwt && rx_q->rx_count_frames;
+
+		use_rx_wd = !priv->rx_coal_frames;
+		use_rx_wd |= rx_q->rx_count_frames > 0;
+		if (!priv->use_riwt)
+			use_rx_wd = false;
 
 		dma_wmb();
 		stmmac_set_rx_owner(priv, p, use_rx_wd);