i40e: flower: Fix return value for unsupported offload

When filter configuration is not supported, drivers should return
-EOPNOTSUPP so the core can react correctly.

Fixes: 2f4b411a3d67 ("i40e: Enable cloud filters via tc-flower")
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/i40e/i40e_main.c

@@ -7371,7 +7371,7 @@ static int i40e_configure_clsflower(struct i40e_vsi *vsi,
 
 	if (tc < 0) {
 		dev_err(&vsi->back->pdev->dev, "Invalid traffic class\n");
-		return -EINVAL;
+		return -EOPNOTSUPP;
 	}
 
 	if (test_bit(__I40E_RESET_RECOVERY_PENDING, pf->state) ||