net/mlx5e: Vxlan, return values for add/del port

For a better API mlx5_vxlan_{add/del}_port can fail, make them return
error values.

Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Reviewed-by: Or Gerlitz <ogerlitz@mellanox.com>
2 files changed