net/mlx5e: fix another maybe-uninitialized false-positive

In commit abeffce ("net/mlx5e: Fix a -Wmaybe-uninitialized warning"), I fixed a
gcc warning for the ipv4 offload handling. Now we get the same warning for the
added ipv6 support:

drivers/net/ethernet/mellanox/mlx5/core/en_tc.c:815:40: warning: 'out_dev' may be used uninitialized in this function [-Wmaybe-uninitialized]

We can apply the same workaround here as well.

Fixes: ce99f6b97f ("net/mlx5e: Support SRIOV TC encapsulation offloads for IPv6 tunnels")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx5/core/en_tc.c

@@ -731,8 +731,8 @@ static int mlx5e_route_lookup_ipv6(struct mlx5e_priv *priv,
 	int ret;
 
 	dst = ip6_route_output(dev_net(mirred_dev), NULL, fl6);
-	if (dst->error) {
-		ret = dst->error;
+	ret = dst->error;
+	if (ret) {
 		dst_release(dst);
 		return ret;
 	}