lsm: infrastructure management of the perf_event security blob

Move management of the perf_event->security blob out of the individual
security modules and into the security infrastructure. Instead of
allocating the blobs from within the modules the modules tell the
infrastructure how much space is required, and the space is allocated
there.  There are no longer any modules that require the perf_event_free()
hook.  The hook definition has been removed.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: John Johansen <john.johansen@canonical.com>
[PM: subject tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>

include/linux/lsm_hooks.h

@@ -79,6 +79,7 @@ struct lsm_blob_sizes {
 	int	lbs_ipc;
 	int	lbs_key;
 	int	lbs_msg_msg;
+	int	lbs_perf_event;
 	int	lbs_task;
 	int	lbs_xattr_count; /* number of xattr slots in new_xattrs array */
 	int	lbs_tun_dev;