9p: remove sysctl

A sysctl method was added to enable and disable debugging levels.  After
further review, it was decided that there are better approaches to doing this
and the sysctl methodology isn't really desirable.  This patch removes the
sysctl code from 9p.

Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
  
4 files changed