Temporary patch to workaround a DMA reset issue with rockchip
devices experienced at least on rk3288 and rk3328 with a message
like this:

rk_gmac-dwmac ff290000.ethernet end0: Failed to reset the dma

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index e0fb06af1f94..156a5d25d1fd 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -3133,8 +3133,8 @@ static int stmmac_init_dma_engine(struct stmmac_priv *priv)
 
 	ret = stmmac_reset(priv, priv->ioaddr);
 	if (ret) {
-		netdev_err(priv->dev, "Failed to reset the dma\n");
-		return ret;
+		netdev_warn(priv->dev, "Failed to reset the dma, device will work with reduced throughput\n");
+		ret = 0;
 	}
 
 	/* DMA Configuration */