block: move the call to get_max_io_size out of blk_bio_segment_split

block: move the call to get_max_io_size out of blk_bio_segment_split

Prepare for reusing blk_bio_segment_split for (file system controlled)
splits of REQ_OP_ZONE_APPEND bios by letting the caller control the
maximum size of the bio.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20220727162300.3089193-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>