hv_netvsc: fix error return code in netvsc_probe()

Fix to return a negative error code from the failover register fail
error handling case instead of 0, as done elsewhere in this function.

Fixes: 1ff78076 ("netvsc: refactor notifier/event handling code to use the failover framework")
Signed-off-by: NWei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/hyperv/netvsc_drv.c

@@ -2031,8 +2031,10 @@ static int netvsc_probe(struct hv_device *dev,
 	}
 
 	net_device_ctx->failover = failover_register(net, &netvsc_failover_ops);
-	if (IS_ERR(net_device_ctx->failover))
+	if (IS_ERR(net_device_ctx->failover)) {
+		ret = PTR_ERR(net_device_ctx->failover);
 		goto err_failover;
+	}
 
 	return ret;