- Add locked variants of init() and start().
- Use callout_*() to manage callout.
- Test IFF_DRV_RUNNING rather than IFF_UP in wb_intr() to see if we are
still active when an interrupt comes in.
I couldn't find any of these cards anywhere to test on myself, and google
turns up references to FreeBSD and OpenBSD manpages for this driver when
trying to locate a card that way. I'm not sure anyone actually uses these
cards with FreeBSD.
Tested by: NO ONE (despite repeated requests)