bce: make compile with BCE_DEBUG

Builds now with BCE_DEBUG defined. All bets are of as to whether or not
it works though. This is not the default, and likely quite a rare config
given (a) it's been broken for years and (b) this is an old card people
aren't actively debugging anymore. I don't have the hardware to test it,
though I've not changed anything in the BCE_DEBUG undefined case.

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