block: pass a max_bio_size argument to bio_iov_iter_get_pages

block: pass a max_bio_size argument to bio_iov_iter_get_pages

Integrity buffer sizing is based on the total amount of blocks
written, which can get enormous with huge folios.  Allow the file system
to tell bio_iov_iter_get_pages to never build bios beyond a given size
limit so that it can always allocate an integrity buffer.

Signed-off-by: Christoph Hellwig <hch@lst.de>