drbd: drbd_insert_interval(): Clarify comment

Signed-off-by: Andreas Gruenbacher <agruen@linbit.com>
Signed-off-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com>
Link: https://lore.kernel.org/r/20230113123538.144276-9-christoph.boehmwalder@linbit.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>