ISDN4BSD cleanup

[Hans Petter Selasky]

Hi,

FreeBSD versions earlier than 8.0 will no longer be supported by my ISDN 
driver in a month or so. I plan to clean up the extra files I have for FreeBSD 
6 and 7 support and clean up the code so that it only works with FreeBSD 
version 8 and later. If anyone has any objections to this then please send me 
an e-mail.

--HPS

Reference: http://www.selasky.org/hans_petter/isdn4bsd