net: stmmac: Correctly assing MAX MTU in XGMAC cores case

Maximum MTU for XGMAC cores is 16k thus the check for presence of XGMAC
shall be done first in order to assign correct value.
Signed-off-by: NJose Abreu <joabreu@synopsys.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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

@@ -4542,10 +4542,10 @@ int stmmac_dvr_probe(struct device *device,
 
 	/* MTU range: 46 - hw-specific max */
 	ndev->min_mtu = ETH_ZLEN - ETH_HLEN;
-	if ((priv->plat->enh_desc) || (priv->synopsys_id >= DWMAC_CORE_4_00))
-		ndev->max_mtu = JUMBO_LEN;
-	else if (priv->plat->has_xgmac)
+	if (priv->plat->has_xgmac)
 		ndev->max_mtu = XGMAC_JUMBO_LEN;
+	else if ((priv->plat->enh_desc) || (priv->synopsys_id >= DWMAC_CORE_4_00))
+		ndev->max_mtu = JUMBO_LEN;
 	else
 		ndev->max_mtu = SKB_MAX_HEAD(NET_SKB_PAD + NET_IP_ALIGN);
 	/* Will not overwrite ndev->max_mtu if plat->maxmtu > ndev->max_mtu