net/mlx5: E-Switch, Remove redundant dev arg from mlx5_esw_vport_alloc()

The passded esw->dev is redundant as esw being passed and esw->dev being
used inside.

Signed-off-by: Roi Dayan <roid@nvidia.com>
Reviewed-by: Maor Dickman <maord@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>