misc/91916: simple update of bktr(4) man page

[Alexander Leidinger]

Synopsis: simple update of bktr(4) man page

Responsible-Changed-From-To: freebsd-bugs->netchild
Responsible-Changed-By: netchild
Responsible-Changed-When: Tue Jan 17 21:41:00 UTC 2006
Responsible-Changed-Why: 
I take this one, since I have some changes to the man-page (supported
hardware) too.

http://www.freebsd.org/cgi/query-pr.cgi?pr=91916