mlxsw: spectrum: Remove limitation regarding VID 1

VID 1 is not reserved anymore, so remove the check that prevented the
creation of VLAN devices with this VID over mlxsw ports.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>