To check wether we are truncating a very large device due to limited
meta data space, we need to check the ll_dev size.

Also improve the printk to suggest "flexible" or "internal".
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>