nvme: Change devctl events for the controller

[imp]

Summary

Change the devctl events slightly for the controller. SMART errors will
log the changed bits in the NVME SMART Critical Warning State as its
event.

Reset will now emit 'event=start'. Soon more.

Sponsored by: Netflix

[mav]

sys/dev/nvme/nvme_ctrlr.c

67–69

I see no space between the parameters neither here nor in the callers.

670

I wonder how convenient is it to handle the state bitmask in devd.conf.

[imp]

add space, per review

[imp]

sys/dev/nvme/nvme_ctrlr.c

670

I think it will be clear enough. State tells you chat changed, and the log page 0 tells you whats' currently active. some amount of parsing by a script will be needed to sort out what's new and what's old anyway, so I think in practice it won't be too bad. If I'm wrong, I'll figure out what to do then... I've thought in the past of augmenting devd.conf to allow better numeric expressions. But if there's ever a good use case for ucl, I think devd.conf might be it.... But both of those are beyond the scope of this change.