io_uring: remove the mode variable in io_file_get_flags

The variable is only once now, so don't bother with it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230620113235.920399-3-hch@lst.de


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