mtd: nand: typo in nand_id_has_period() comments

The simple example provided in the comments for nand_id_has_period()
actually has a period of 3, not 2. Silly mistake...

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

drivers/mtd/nand/nand_base.c

@@ -2923,7 +2923,7 @@ static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip,
  *
  * Check if an ID string is repeated within a given sequence of bytes at
  * specific repetition interval period (e.g., {0x20,0x01,0x7F,0x20} has a
- * period of 2). This is a helper function for nand_id_len(). Returns non-zero
+ * period of 3). This is a helper function for nand_id_len(). Returns non-zero
  * if the repetition has a period of @period; otherwise, returns zero.
  */
 static int nand_id_has_period(u8 *id_data, int arrlen, int period)