to check the status property in their probe routines.
Simplebus used to only instantiate its children whose status="okay"
but that was improper behavior, fixed in r261352. Now that it doesn't
check anymore and probes all its children; the children all have to
do the check because really only the children know how to properly
interpret their status property strings.
Right now all existing drivers only understand "okay" versus something-
that's-not-okay, so they all use the new ofw_bus_status_okay() helper.
Terasic DE-4 board. Allow LED configuration to be set using loader
tunables, not just from userspace, and preconfigure LED 8 as a kernel
heartbeat. For now, this is a Nexus-attached, BERI-only driver, but it
could be used with other hard and soft cores on Altera FPGAs as well, in
principle.
Sponsored by: DARPA, AFRL
