dm: call blk_queue_split() to impose device limits on bios

Otherwise the incoming bios, of various types, won't be shaped based on
the DM device's advertised limits.

Depends-on: af67c31f ("blk: remove bio_set arg from blk_queue_split()")
Fixes: 744889b7 ("block: don't deal with discard limit in blkdev_issue_discard()")
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>