security/tomoyo: Remove now unnecessary handling of security_sysctl.

Now that sys_sysctl is an emulation on top of proc sys all sysctl
operations look like normal filesystem operations and we don't need
to use the special sysctl hook to authenticate them.

Acked-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>