I tested with latest ISO from http://cdimage.debian.org/cdimage/weekly-builds/arm64/iso-dvd/debian-testing-arm64-DVD-1.iso (16-May-2016) and the network adapter was not working.
When I passed the kernel parameter clk_ignore_unused, the network adapter worked without issue. The installer successfully obtained an IP address and was able to download all files required for installation. More information about the use of clk_ignore_unused work-around and the issues with xgene_enet when compiled as module can be found here: https://bugzilla.suse.com/show_bug.cgi?id=973756
