mlxsw: spectrum: Iterate over all ports in gap during unsplit create

During recreation of original unsplit ports, just simply iterate over
the whole gap and recreate whatever originally existed.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: Shalom Toledo <shalomt@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>