[BLOCK] dm-crypt: trivial comment improvements

Just some minor comment nits.

- little-endian is better than low-endian
- and since it is called essiv everywere it should also be essiv
  in the comments (and not ess_iv)
Signed-off-by: Rik Snel <rsnel@cube.dyndns.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/md/dm-crypt.c

@@ -99,10 +99,10 @@ static kmem_cache_t *_crypt_io_pool;
 /*
  * Different IV generation algorithms:
  *
- * plain: the initial vector is the 32-bit low-endian version of the sector
+ * plain: the initial vector is the 32-bit little-endian version of the sector
  *        number, padded with zeros if neccessary.
  *
- * ess_iv: "encrypted sector|salt initial vector", the sector number is
+ * essiv: "encrypted sector|salt initial vector", the sector number is
  *        encrypted with the bulk cipher using a salt as key. The salt
  *        should be derived from the bulk cipher's key via hashing.
  *