R35.2.1 PCIe i210 throughput slow

@DaneLLL I have now tried R35.2.1 as suggested here [R35.1 PCIe i210 throughput slow - #12 by DaneLLL] but unfortunately I’m finding the same results as R35.1 i.e. there is slow Tx throughput on the PCIe.

I also see the same issue when flashing our board with ./flash.sh jetson-xavier-nx-devkit-emmc i.e. using the reference devkit device tree / root filesystem, so am thinking this isn’t a local configuration issue of some sort.