BIOS_NEVER -> BIOS_SPEW+1

The whole intent was to make clear to the reader that this is something that's never seen. ;-)
That doesn't become clear from BIOS_SPEW+1 in my opinion.
NEVER was only used once or twice in the code. If it's something that will be used more often, then I can see your point. Why don't we just comment out messages that will never be seen?

I just looked again, and it was only used once. It makes sense where it was used, but I don't think it makes sense to use it other places, and I think naming it with the same prefix and including it in the same list makes that likely in the future.

I think a comment explaining BIOS_SPEW+1 would work just as well, or this:
BIOS_NEVER -> CONFIG_MAXIMUM_CONSOLE_LOGLEVEL+1

Thanks,
Myles