mtd: spi-nor: atmel: add at25ff321a entry

Add the at25ff321a 4MB SPI flash which is able to provide
SFDP information.
Link: https://www.renesas.com/us/en/document/dst/at25ff321a-datasheet



Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Link: https://lore.kernel.org/r/20230926131655.51224-1-nicolas.ferre@microchip.com


Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>