net/mlx5e: Remove redundant vport context vlan update

In delete vlan flow an extra call to mlx5e_vport_context_update_vlans
was added by mistake, remove it.

Fixes: 86d722ad ("net/mlx5: Use flow steering infrastructure for mlx5_en")
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Reviewed-by: Gal Pressman <galp@mellanox.com>