Partial merge r198987:
  Use device_printf() and if_printf() instead of printf() with an explicit
  unit number and remove 'unit' members from softc.

Partial merge r199414:
  Use the bus_*() routines rather than bus_space_*() for register operations.

r199543:
  Several fixes to this driver:
  - Overhaul the locking to avoid recursion and add missing locking in a few
    places.
  - Don't schedule a task to call vge_start() from contexts that are safe to
    call vge_start() directly.  Just invoke the routine directly instead
    (this is what all of the other NIC drivers I am familiar with do).  Note
    that vge(4) does not use an interrupt filter handler which is the primary
    reason some other drivers use tasks.
  - Add a new private timer to drive the watchdog timer instead of using
    if_watchdog and if_timer.
  - Fixup detach by calling ether_ifdetach() before stopping the interface.

r200422:
  Remove driver lock assertion in MII register access. This change
  was made in r199543 to remove MTX_RECURSE. These routines can be
  called in device attach phase(e.g. mii_phy_probe()) so checking
  assertion here is not right as caller does not hold a driver lock.