net/stmmac: fix issue of clk_get for Loongson1B.

When getting clock, give a chance to the CPUs without DT support,
which use Common Clock Framework, such as Loongson1B.

Signed-off-by: Kelvin Cheung <keguang.zhang@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -2077,7 +2077,7 @@ struct stmmac_priv *stmmac_dvr_probe(struct device *device,
 		goto error_netdev_register;
 	}
 
-	priv->stmmac_clk = clk_get(priv->device, NULL);
+	priv->stmmac_clk = clk_get(priv->device, STMMAC_RESOURCE_NAME);
 	if (IS_ERR(priv->stmmac_clk)) {
 		pr_warning("%s: warning: cannot get CSR clock\n", __func__);
 		goto error_clk_get;