net: dsa: ksz: ksz8863_smi_probe: set proper return value for ksz_switch_alloc()

ksz_switch_alloc() will return NULL only if allocation is failed. So,
the proper return value is -ENOMEM.

Fixes: 60a36476 ("net: dsa: microchip: Add Microchip KSZ8863 SMI based driver support")
Signed-off-by: NOleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/dsa/microchip/ksz8863_smi.c

@@ -154,7 +154,7 @@ static int ksz8863_smi_probe(struct mdio_device *mdiodev)
 
 	dev = ksz_switch_alloc(&mdiodev->dev, ksz8);
 	if (!dev)
-		return -EINVAL;
+		return -ENOMEM;
 
 	for (i = 0; i < ARRAY_SIZE(ksz8863_regmap_config); i++) {
 		rc = ksz8863_regmap_config[i];