block: stop setting ->direct_IO

Direct I/O on block devices now nevers goes through aops->direct_IO.
Stop setting it and set the FMODE_CAN_ODIRECT in ->open instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20230801172201.1923299-5-hch@lst.de


Signed-off-by: Jens Axboe <axboe@kernel.dk>