k64f: change flash device name
Recent Zephyr changes the flash device name.  Change to match it.
* @brief Bootloader device specific configuration.
*/
-#define FLASH_DRIVER_NAME "KSDK_FLASH"
+#define FLASH_DRIVER_NAME "MCUX_FLASH"
#define FLASH_ALIGN 8
#define FLASH_AREA_IMAGE_0_OFFSET 0x20000
#define FLASH_AREA_IMAGE_0_SIZE 0x20000
