block: move the BIO_CLONED checks out of __bio_try_merge_page

__bio_try_merge_page is a way too low-level helper to assert that the
bio is not cloned.  Move the check into bio_add_page and
bio_iov_iter_get_pages instead, which are the high level entry points
that should enforce this variant.  bio_add_hw_page already this
check, coverig the third (indirect) caller of __bio_try_merge_page.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jinyoung Choi <j-young.choi@samsung.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20230724165433.117645-4-hch@lst.de


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