Revert "mtd: spinand: Fix OOB read"

This reverts stable commit baad618d.

This commit is adding lines to spinand_write_to_cache_op, wheras the upstream
commit 868cbe2a that this was supposed to
backport was touching spinand_read_from_cache_op.
It causes a crash on writing OOB data by attempting to write to read-only
kernel memory.

Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>