net: dsa: mt7530: remove .mac_port_config for MT7988 and make it optional

For the switch on the MT7988 SoC, the mac_port_config member for ID_MT7988
in mt753x_table is not needed as the interfaces of all MACs are already
handled on mt7988_mac_port_get_caps().

Therefore, remove the mac_port_config member from ID_MT7988 in
mt753x_table. Before calling priv->info->mac_port_config(), if there's no
mac_port_config member in mt753x_table, exit mt753x_mac_config()
successfully.

Remove calling priv->info->mac_port_config() from the sanity check as the
sanity check requires a pointer to a mac_port_config function to be
non-NULL. This will fail for MT7988 as mac_port_config won't be a member of
its info table.
Co-developed-by: Daniel Golle <daniel@makrotopia.org>
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Signed-off-by: Arınç ÜNAL <arinc.unal@arinc9.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

drivers/net/dsa/mt7530.c

@@ -2655,17 +2655,6 @@ static bool mt753x_is_mac_port(u32 port)
 	return (port == 5 || port == 6);
 }
 
-static int
-mt7988_mac_config(struct dsa_switch *ds, int port, unsigned int mode,
-		  phy_interface_t interface)
-{
-	if (dsa_is_cpu_port(ds, port) &&
-	    interface == PHY_INTERFACE_MODE_INTERNAL)
-		return 0;
-
-	return -EINVAL;
-}
-
 static int
 mt7531_mac_config(struct dsa_switch *ds, int port, unsigned int mode,
 		  phy_interface_t interface)
@@ -2706,6 +2695,9 @@ mt753x_mac_config(struct dsa_switch *ds, int port, unsigned int mode,
 {
 	struct mt7530_priv *priv = ds->priv;
 
+	if (!priv->info->mac_port_config)
+		return 0;
+
 	return priv->info->mac_port_config(ds, port, mode, state->interface);
 }
 
@@ -3169,7 +3161,6 @@ const struct mt753x_info mt753x_table[] = {
 		.phy_write_c45 = mt7531_ind_c45_phy_write,
 		.cpu_port_config = mt7988_cpu_port_config,
 		.mac_port_get_caps = mt7988_mac_port_get_caps,
-		.mac_port_config = mt7988_mac_config,
 	},
 };
 EXPORT_SYMBOL_GPL(mt753x_table);
@@ -3197,8 +3188,7 @@ mt7530_probe_common(struct mt7530_priv *priv)
 	 * properly.
 	 */
 	if (!priv->info->sw_setup || !priv->info->phy_read_c22 ||
-	    !priv->info->phy_write_c22 || !priv->info->mac_port_get_caps ||
-	    !priv->info->mac_port_config)
+	    !priv->info->phy_write_c22 || !priv->info->mac_port_get_caps)
 		return -EINVAL;
 
 	priv->id = priv->info->id;