ice: Add support for changing MTU on PR in switchdev mode

This change adds support for changing MTU on port representor in
switchdev mode, by setting the min/max MTU values on port representor
netdev. Before it was possible to change the MTU only in a limited,
default range (68-1500).

Signed-off-by: Marcin Szycik <marcin.szycik@intel.com>
Tested-by: Sandeep Penigalapati <sandeep.penigalapati@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

drivers/net/ethernet/intel/ice/ice_repr.c

@@ -267,6 +267,9 @@ static int ice_repr_add(struct ice_vf *vf)
 	if (err)
 		goto err_devlink;
 
+	repr->netdev->min_mtu = ETH_MIN_MTU;
+	repr->netdev->max_mtu = ICE_MAX_MTU;
+
 	err = ice_repr_reg_netdev(repr->netdev);
 	if (err)
 		goto err_netdev;