MFC if_re.c rev. 1.95 to RELENG_6.

MFC if_re.c rev. 1.95 to RELENG_6.
  Make sure to take PHY out of power down mode in device attach.
  Without this the PHY wouldn't work as expected. This should fix
  dual-boot Windows XP machine where RealTek Windows drivers put the
  PHY in power down mode during shutdown. The magic PHY register
  accesses come from RealTek driver. No datasheets mention the magic
  PHY registers.
  In general, the PHY wakeup code should go into PHY driver. However it
  seems that it only apply to RTL8169S single chip and it would be
  another hack if we have rgephy(4) check what parent driver/chip model
  is attached.