net: stmmac: Move device_can_wakeup() check earlier in set_wol

If !device_can_wakeup(), there's no need to futher check. And return
-EOPNOTSUPP rather than -EINVAL if !device_can_wakeup().
Signed-off-by: NJisheng Zhang <Jisheng.Zhang@synaptics.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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

@@ -615,15 +615,15 @@ static int stmmac_set_wol(struct net_device *dev, struct ethtool_wolinfo *wol)
 	struct stmmac_priv *priv = netdev_priv(dev);
 	u32 support = WAKE_MAGIC | WAKE_UCAST;
 
+	if (!device_can_wakeup(priv->device))
+		return -EOPNOTSUPP;
+
 	/* By default almost all GMAC devices support the WoL via
 	 * magic frame but we can disable it if the HW capability
 	 * register shows no support for pmt_magic_frame. */
 	if ((priv->hw_cap_support) && (!priv->dma_cap.pmt_magic_frame))
 		wol->wolopts &= ~WAKE_MAGIC;
 
-	if (!device_can_wakeup(priv->device))
-		return -EINVAL;
-
 	if (wol->wolopts & ~support)
 		return -EINVAL;