f2fs: don't pass a bio to f2fs_target_device

Set the bdev at bio allocation time by changing the f2fs_target_device
calling conventions, so that no bio needs to be passed in.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chao Yu <chao@kernel.org>
Link: https://lore.kernel.org/r/20220228124123.856027-2-hch@lst.de


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