- Use bus_foo() rather than bus_space_foo() and retire the bus tag and handle

- Use bus_foo() rather than bus_space_foo() and retire the bus tag and handle
  from the softc.
- Rework the watchdog timer to match other NIC drivers:
  - Start a timer in fe_init() that runs once a second and checks a counter
    in the softc that is identical to the deprecated 'if_timer'.
  - Just adjust the softc tx timeout value when sending packets instead of
    scheduling the timer.
- Use IFQ_SET_MAXLEN().

Tested by:	WATANABE Kazuhiro