mtd: spi-nor: default page_size to 256 bytes

The INFO() macro always set the page_size to 256 bytes. Make that an
optional parameter. This default is a sane one for all older flashes,
newer ones will set the page size by its SFDP tables anyway.

Signed-off-by: Michael Walle <mwalle@kernel.org>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/r/20230807-mtd-flash-info-db-rework-v3-6-e60548861b10@kernel.org


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