net: mediatek: dropped rx packets are not being counted properly

There are two places inside mtk_poll_rx where rx_dropped is not being
incremented properly. Fix this by adding the missing code to increment
the counter.
Signed-off-by: NJohn Crispin <john@phrozen.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/mediatek/mtk_eth_soc.c

@@ -829,6 +829,7 @@ static int mtk_poll_rx(struct napi_struct *napi, int budget,
 					  DMA_FROM_DEVICE);
 		if (unlikely(dma_mapping_error(&netdev->dev, dma_addr))) {
 			skb_free_frag(new_data);
+			netdev->stats.rx_dropped++;
 			goto release_desc;
 		}
 
@@ -836,6 +837,7 @@ static int mtk_poll_rx(struct napi_struct *napi, int budget,
 		skb = build_skb(data, ring->frag_size);
 		if (unlikely(!skb)) {
 			put_page(virt_to_head_page(new_data));
+			netdev->stats.rx_dropped++;
 			goto release_desc;
 		}
 		skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);