net/mlx5: E-switch, Introduce flag to indicate if vport acl namespace is created

Eswitch vport acl namespace is needed when loading vfs. There is
no need to free and reallocate it when switching eswitch mode.
Introduce flag to indicate if it is created or not. When needed,
create it. Only free it when the driver is unloaded or in bare
metal mode.

Signed-off-by: Chris Mi <cmi@nvidia.com>
Reviewed-by: Mark Bloch <mbloch@nvidia.com>
Reviewed-by: Roi Dayan <roid@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>