The Marvell 98DX7335 switch ASIC has 32 lanes that can be configured any way the vendor wants. There aren't any fuses and it can even be reconfigured at runtime (e.g. a 400G port can be split into 2x200G).

Are the smaller 98DX7325 and 98DX7321 the same chip with fuses blown? I wouldn't be surprised.