mtd: spi-nor: remove or move flash_info comments

Most of the comments are a relict of the past when the flash_info was
just one table. Most of them are useless. Remove them.

Signed-off-by: Michael Walle <mwalle@kernel.org>
Link: https://lore.kernel.org/r/20230807-mtd-flash-info-db-rework-v3-16-e60548861b10@kernel.org


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