MFC r251481:

MFC r251481:
  Do not report current link status if driver is not running.
  Reporting link status in driver has a side-effect that makes mii(4)
  check current link status.  mii(4) will call link status change
  callback when it sees link state change.  Normally this wouldn't
  have problems. However, ASF/IPMI firmware can actively access PHY
  regardless of driver's running state such that reporting link
  status for not-running interface can generate meaningless link
  UP/DOWN messages.

  This change also makes dhclient think driver got a valid link
  regardless of link establishment so it will bypass dhclient's
  initial link status check. I think that wouldn't be issue
  though.

git-svn-id: svn://svn.freebsd.org/base/stable/9@252452 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f