RFT: improvements to if_cdce driver

From: John-Mark Gurney <jmg_at_funkthat.com>
Date: Thu, 03 Jun 2021 06:20:14 UTC
Hello,

I decided to make some improvements to the CDCE driver as at least
the RealTek devices (what I tested them with) when they aren't supported
by ure will present as cdce devices.

https://reviews.freebsd.org/D30625

This adds if_media support and link state support.

The most significant change is this means that if a ue device is
configured for DHCP, devd will now launch dhclient, where previously
it would not, as it would neither receive the link up status (for when
a cable is plugged in) nor would it be the requisit ethernet media
type.

The device I tested with was a RealTek 2.5G device.  So, other
non-RealTek devices would be great to test with.

Let me know if you have any issues with the change!

Thanks.

-- 
  John-Mark Gurney				Voice: +1 415 225 5579

     "All that I will do, has been done, All that I have, has not."