TOMOYO: Remove usage counter for temporary memory.

TOMOYO was using own memory usage counter for detecting memory leak.
But as kernel 2.6.31 introduced memory leak detection mechanism
( CONFIG_DEBUG_KMEMLEAK ), we no longer need to have own counter.

We remove usage counter for memory used for permission checks, but we keep
usage counter for memory used for policy so that we can apply quota.

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