dm delay: use msecs_to_jiffies for time conversion

Converting milliseconds to jiffies by "val * HZ / 1000" is technically
OK but msecs_to_jiffies(val) is the cleaner solution and handles all
corner cases correctly.
Signed-off-by: NNicholas Mc Guire <hofrat@osadl.org>
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

drivers/md/dm-delay.c

@@ -236,7 +236,7 @@ static int delay_bio(struct delay_c *dc, int delay, struct bio *bio)
 	delayed = dm_per_bio_data(bio, sizeof(struct dm_delay_info));
 
 	delayed->context = dc;
-	delayed->expires = expires = jiffies + (delay * HZ / 1000);
+	delayed->expires = expires = jiffies + msecs_to_jiffies(delay);
 
 	mutex_lock(&delayed_bios_lock);