cls_flower: fix error values for commands not supported by drivers

-EOPNOTSUPP is the error value that should be reported if a flower
command is not supported by a driver. Fix it in couple of Intel drivers.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -7522,7 +7522,7 @@ static int i40e_setup_tc_cls_flower(struct i40e_netdev_priv *np,
 	case TC_CLSFLOWER_STATS:
 		return -EOPNOTSUPP;
 	default:
-		return -EINVAL;
+		return -EOPNOTSUPP;
 	}
 }