selinux: apply selinux checks on new audit message types

We use the read check to get the feature set (like AUDIT_GET) and the
write check to set the features (like AUDIT_SET).

Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Eric Paris <eparis@redhat.com>