mtd: spinand: Explicitly use MTD_OPS_RAW to write the bad block marker to OOB

mtd: spinand: Explicitly use MTD_OPS_RAW to write the bad block marker to OOB

When writing the bad block marker to the OOB area the access mode
should be set to MTD_OPS_RAW as it is done for reading the marker.
Currently this only works because req.mode is initialized to
MTD_OPS_PLACE_OOB (0) and spinand_write_to_cache_op() checks for
req.mode != MTD_OPS_AUTO_OOB.

Fix this by explicitly setting req.mode to MTD_OPS_RAW.

Fixes: 9d920af6b0c0 ("mtd: nand: Add core infrastructure to support SPI NANDs")
Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20200218100432.32433-3-frieder.schrempf@kontron.de