dm bio prison v2: use true/false for bool variable

Fixes coccicheck warning:

drivers/md/dm-bio-prison-v2.c:327:2-22: WARNING: Assignment of 0/1 to bool variable
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: zhengbin <zhengbin13@huawei.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

drivers/md/dm-bio-prison-v2.c

@@ -324,7 +324,7 @@ static bool __unlock(struct dm_bio_prison_v2 *prison,
 	bio_list_init(&cell->bios);
 
 	if (cell->shared_count) {
-		cell->exclusive_lock = 0;
+		cell->exclusive_lock = false;
 		return false;
 	}