net: dsa: sja1105: Avoid error message for unknown PHY mode on disabled ports

When sja1105_init_mii_settings iterates over the port list, it prints
this message for disabled ports, because they don't have a valid
phy-mode:

[    4.778702] sja1105 spi2.0: Unsupported PHY mode unknown!
Suggested-by: Andrew Lunn <andrew@lunn.ch>
Suggested-by: Vivien Didelot <vivien.didelot@gmail.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Vivien Didelot <vivien.didelot@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/sja1105/sja1105_main.c

@@ -162,6 +162,9 @@ static int sja1105_init_mii_settings(struct sja1105_private *priv,
 	mii = table->entries;
 
 	for (i = 0; i < SJA1105_NUM_PORTS; i++) {
+		if (dsa_is_unused_port(priv->ds, i))
+			continue;
+
 		switch (ports[i].phy_mode) {
 		case PHY_INTERFACE_MODE_MII:
 			mii->xmii_mode[i] = XMII_MODE_MII;