net: hns3: fix for returning wrong value problem in hns3_get_rss_key_size

The return type of hns3_get_rss_key_size is u32. But a negative value is
returned. This patch fixes it by replacing the negative value with zero.
Signed-off-by: NFuyun Liang <liangfuyun1@huawei.com>
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c

@@ -638,7 +638,7 @@ static u32 hns3_get_rss_key_size(struct net_device *netdev)
 
 	if (!h->ae_algo || !h->ae_algo->ops ||
 	    !h->ae_algo->ops->get_rss_key_size)
-		return -EOPNOTSUPP;
+		return 0;
 
 	return h->ae_algo->ops->get_rss_key_size(h);
 }