other fixes:
- Add pointers back to device_t objects in softc structures instead
of storing the unit and using devclass_get_device().
- Add 'lpbb', 'pcf', 'pps', and 'vpo' child devices to every 'ppbus' device
instead of just the first one.
- Store softc pointers in si_drv1 of character devices instead of
pulling the unit number from the minor number and using
devclass_get_softc() and devclass_get_device().
- Store the LP_BYPASS flag in si_drv2 instead of encoding it in the minor
number.
- Destroy character devices for lpt(4) when detaching the device.
- Use bus_print_child_footer() instead of duplicating it in
ppbus_print_child() and fix ppbus_print_child()'s return value.
- Remove unused AVM ivar from ppbus.
- Don't store the 'mode' ivar in the ppbus ivars since we always fetch it
from the parent anyway.
- Try to detach all the child devices before deleting them in
ppbus_detach().
- Use pause() instead of a tsleep() on a dummy address when polling the
ppbus.
- Use if_printf() and device_printf() instead of explicit names with unit
numbers.
Silence on: current@
03f7a1b892