net: dsa: microchip: make phylink_mac_link_up() not optional

Last part of the driver do now support phylink_mac_link_up(). So, make it
not optional.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://lore.kernel.org/r/20231127145101.3039399-4-o.rempel@pengutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/dsa/microchip/ksz_common.c

@@ -3113,10 +3113,8 @@ static void ksz_phylink_mac_link_up(struct dsa_switch *ds, int port,
 {
 	struct ksz_device *dev = ds->priv;
 
-	if (dev->dev_ops->phylink_mac_link_up)
-		dev->dev_ops->phylink_mac_link_up(dev, port, mode, interface,
-						  phydev, speed, duplex,
-						  tx_pause, rx_pause);
+	dev->dev_ops->phylink_mac_link_up(dev, port, mode, interface, phydev,
+					  speed, duplex, tx_pause, rx_pause);
 }
 
 static int ksz_switch_detect(struct ksz_device *dev)