net/mlx5e: Fix memory leak on updating vport counters

When updating statistics driver queries the vport's counters. On fail,
add error path releasing the allocated buffer avoiding memory leak.

Fixes: 64b68e36 ("net/mlx5: Refactor and expand rep vport stat group")
Signed-off-by: Aya Levin <ayal@nvidia.com>
Reviewed-by: Maor Dickman <maord@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

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

@@ -191,7 +191,7 @@ static MLX5E_DECLARE_STATS_GRP_OP_UPDATE_STATS(vport_rep)
 	if (err) {
 		netdev_warn(priv->netdev, "vport %d error %d reading stats\n",
 			    rep->vport, err);
-		return;
+		goto out;
 	}
 
 	#define MLX5_GET_CTR(p, x) \
@@ -241,6 +241,7 @@ static MLX5E_DECLARE_STATS_GRP_OP_UPDATE_STATS(vport_rep)
 	rep_stats->tx_vport_rdma_multicast_bytes =
 		MLX5_GET_CTR(out, received_ib_multicast.octets);
 
+out:
 	kvfree(out);
 }