the channel_mask field of struct audio_format is unused, so removed it and the associated macros.  this is part of NetBSD's "converter pipeline", and it isn't really used there either.
the channel_mask field of struct audio_format is unused, so removed
it and the associated macros.  this is part of NetBSD's "converter
pipeline", and it isn't really used there either.

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