drbd: drbd_insert_interval(): Clarify comment

Signed-off-by: Andreas Gruenbacher <[e-mail]>
Signed-off-by: Christoph Böhmwalder <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jens Axboe <[e-mail]>

drivers/block/drbd/drbd_interval.c

···
  * drbd_contains_interval  -  check if a tree contains a given interval
  * @root:	red black tree root
  * @sector:	start sector of @interval
- * @interval:	may not be a valid pointer
+ * @interval:	may be an invalid pointer
  *
  * Returns if the tree contains the node @interval with start sector @start.
  * Does not dereference @interval until @interval is known to be a valid object