dm-integrity: set max_integrity_segments in dm_integrity_io_hints

Set max_integrity_segments with the other queue limits instead
of updating it later.  This also uncovered that the driver is trying
to set the limit to UINT_MAX while max_integrity_segments is an
unsigned short, so fix it up to use USHRT_MAX instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>