TOMOYO: Explicitly set file_operations->llseek pointer.

TOMOYO does not deal offset pointer. Thus seek operation makes
no sense. Changing default seek operation from default_llseek()
to no_llseek() might break some applications. Thus, explicitly
set noop_llseek().

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>