net: dsa: mv88e6xxx: Provide dummy implementations for trunk setters

Support for Global 2 registers is build-time optional. In the case
where it was not enabled the build would fail as no "dummy"
implementation of these functions was available.

Fixes: 57e661aa ("net: dsa: mv88e6xxx: Link aggregation support")
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Tested-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/dsa/mv88e6xxx/global2.h

@@ -525,6 +525,18 @@ static inline int mv88e6xxx_g2_trunk_clear(struct mv88e6xxx_chip *chip)
 	return -EOPNOTSUPP;
 }
 
+static inline int mv88e6xxx_g2_trunk_mask_write(struct mv88e6xxx_chip *chip,
+						int num, bool hash, u16 mask)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int mv88e6xxx_g2_trunk_mapping_write(struct mv88e6xxx_chip *chip,
+						   int id, u16 map)
+{
+	return -EOPNOTSUPP;
+}
+
 static inline int mv88e6xxx_g2_device_mapping_write(struct mv88e6xxx_chip *chip,
 						    int target, int port)
 {