linux-phytec-fsl

mtd: atmel_nand: fix typo in dev_err error message

Fix typo, "Unkown" -> "Unknown"

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Josh Wu <josh.wu@atmel.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>