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 <[e-mail]>
Suggested-by: Vivien Didelot <[e-mail]>
Signed-off-by: Vladimir Oltean <[e-mail]>
Reviewed-by: Florian Fainelli <[e-mail]>
Reviewed-by: Vivien Didelot <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/dsa/sja1105/sja1105_main.c

···
 	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;