mtd: spi-nor: mark the flash name as obsolete

The flash name is unreliable as we saw flash ID collisions. Mark the
name as obsolete.

Reviewed-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20231215082138.16063-3-tudor.ambarus@linaro.org


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