net: stmmac: Update RX Tail Pointer to last free entry

Update the RX Tail Pointer to the last available SKB entry.
Signed-off-by: Jose Abreu <joabreu@synopsys.com>
Cc: Joao Pinto <jpinto@synopsys.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -3347,6 +3347,8 @@ static inline void stmmac_rx_refill(struct stmmac_priv *priv, u32 queue)
 		entry = STMMAC_GET_ENTRY(entry, DMA_RX_SIZE);
 	}
 	rx_q->dirty_rx = entry;
+	rx_q->rx_tail_addr = rx_q->dma_rx_phy +
+			    (rx_q->dirty_rx * sizeof(struct dma_desc));
 	stmmac_set_rx_tail_ptr(priv, priv->ioaddr, rx_q->rx_tail_addr, queue);
 }