usb-lan adapter does not work in 10.0-RC4

[Huub Schuurmans]

USB-LAN adapters with the ASIX AX88772 chip do not work properly on
10.0-RC4, whereas thera are no problems with 9.0-RELEASE.
Ping and dhcp work, ssh and http do not.
Adapters that use  if_aue, if_udav or if_mos work fine.

The full description of the tests is reported in PR
http://www.freebsd.org/cgi/query-pr.cgi?pr=185387

Any suggestion how to debug this driver is very welcome,
kind regards,
Huub