RDMA/hns: Fix memory corruption when allocating XRCDN

It's incorrect to cast the type of pointer to xrcdn from (u32 *) to
(unsigned long *), then pass it into hns_roce_bitmap_alloc(), this will
lead to a memory corruption.

Fixes: 32548870 ("RDMA/hns: Add support for XRC on HIP09")
Link: https://lore.kernel.org/r/1616381069-51759-1-git-send-email-liweihang@huawei.comReported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Weihang Li <liweihang@huawei.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/hw/hns/hns_roce_pd.c

@@ -140,8 +140,16 @@ void hns_roce_cleanup_uar_table(struct hns_roce_dev *hr_dev)
 
 static int hns_roce_xrcd_alloc(struct hns_roce_dev *hr_dev, u32 *xrcdn)
 {
-	return hns_roce_bitmap_alloc(&hr_dev->xrcd_bitmap,
-				     (unsigned long *)xrcdn);
+	unsigned long obj;
+	int ret;
+
+	ret = hns_roce_bitmap_alloc(&hr_dev->xrcd_bitmap, &obj);
+	if (ret)
+		return ret;
+
+	*xrcdn = obj;
+
+	return 0;
 }
 
 static void hns_roce_xrcd_free(struct hns_roce_dev *hr_dev,