xfs: simplify xfs_rw_bdev

Delegate to bdev_rw_virt when operating on non-vmalloc memory and use
bio_add_vmalloc_chunk to insulate xfs from the details of adding vmalloc
memory to a bio.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20250507120451.4000627-17-hch@lst.de


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