dm: make __send_duplicate_bios return unsigned int

All the callers cast the value returned by __send_duplicate_bios to
unsigned int type, so we can return unsigned int as well.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

drivers/md/dm.c

@@ -1506,8 +1506,8 @@ static void alloc_multiple_bios(struct bio_list *blist, struct clone_info *ci,
 	}
 }
 
-static int __send_duplicate_bios(struct clone_info *ci, struct dm_target *ti,
-				 unsigned int num_bios, unsigned int *len)
+static unsigned int __send_duplicate_bios(struct clone_info *ci, struct dm_target *ti,
+					  unsigned int num_bios, unsigned int *len)
 {
 	struct bio_list blist = BIO_EMPTY_LIST;
 	struct bio *clone;