SELinux: Reduce max avtab size to avoid page allocation failures

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=570433

Reported-by:  Russell Coker <russell@coker.com.au>
Signed-off-by:  Stephen D. Smalley <sds@tycho.nsa.gov>
Acked-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>

security/selinux/ss/avtab.h

@@ -82,7 +82,7 @@ struct avtab_node *avtab_search_node_next(struct avtab_node *node, int specified
 void avtab_cache_init(void);
 void avtab_cache_destroy(void);
 
-#define MAX_AVTAB_HASH_BITS 13
+#define MAX_AVTAB_HASH_BITS 11
 #define MAX_AVTAB_HASH_BUCKETS (1 << MAX_AVTAB_HASH_BITS)
 #define MAX_AVTAB_HASH_MASK (MAX_AVTAB_HASH_BUCKETS-1)
 #define MAX_AVTAB_SIZE MAX_AVTAB_HASH_BUCKETS