Restore the original wdcdebug_mask instead of clearing DEBUG_PROBE when done with it.  This makes "wdcprobe()" consistent with "wdcattach()".
Restore the original wdcdebug_mask instead of clearing DEBUG_PROBE when
done with it.  This makes "wdcprobe()" consistent with "wdcattach()".

ok grange@

orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars