net/mlx5: Don't perform lookup after already known sec_path

There is no need to perform extra lookup in order to get already
known sec_path that was set a couple of lines above. Simply reuse it.
Reviewed-by: Raed Salem <raeds@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

drivers/net/ethernet/mellanox/mlx5/core/en_accel/ipsec_rxtx.c

@@ -332,7 +332,6 @@ void mlx5e_ipsec_offload_handle_rx_skb(struct net_device *netdev,
 		return;
 	}
 
-	sp = skb_sec_path(skb);
 	sp->xvec[sp->len++] = xs;
 	sp->olen++;