mtd: Fix function description in part_validate comment

The part_validate comment had a wrong description of the actions it
does and referenced to non-existent functions while in fact it calls
'part_validate_eraseblock()'.

Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>

common/cmd_mtdparts.c

@@ -381,10 +381,9 @@ static int part_validate_eraseblock(struct mtdids *id, struct part_info *part)
 
 
 /**
- * Performs sanity check for supplied partition. Offset and size are verified
- * to be within valid range. Partition type is checked and either
- * parts_validate_nor() or parts_validate_nand() is called with the argument
- * of part.
+ * Performs sanity check for supplied partition. Offset and size are
+ * verified to be within valid range. Partition type is checked and
+ * part_validate_eraseblock() is called with the argument of part.
  *
  * @param id of the parent device
  * @param part partition to validate