Reduce MAX_AVTAB_HASH_BITS so that the avtab allocation is an order 2
allocation rather than an order 4 allocation on x86_64.  This
addresses reports of page allocation failures:
http://marc.info/?l=selinux&m=126757230625867&w=2
https://bugzilla.redhat.com/show_bug.cgi?id=570433Reported-by: NRussell Coker <russell@coker.com.au>
Signed-off-by: NStephen D. Smalley <sds@tycho.nsa.gov>
Acked-by: NEric Paris <eparis@redhat.com>
Signed-off-by: NJames Morris <jmorris@namei.org>