removing assumptions that there are only two B channels and by
adding support for a varying number of channels.
Due to this, rename previously used isdn identified "bri" to "isdnif",
which better describes the current situation.
make it pretty simple to write drivers for cards which conform to CAPI.
This code was originally written by Juha-Matti Liukkonen <jml@cubical.fi>
of Cubical Solutions Ltd. for FreeBSD, and was now adapted to NetBSD
by myself for the same company.
christos