net/mlx5e: Slightly reduce hardware LRO size

Before this patch LRO size was 64K, now with build_skb requires
extra room, headroom + sizeof(skb_shared_info) added to the data
buffer will make  wqe size or page_frag_size slightly larger than
64K which will demand order 5 page instead of order 4 in 4K page systems.

We take those extra bytes from hardware LRO data size in order to not
increase the required page order for when hardware LRO is enabled.
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -3188,7 +3188,10 @@ static void mlx5e_build_nic_netdev_priv(struct mlx5_core_dev *mdev,
 				      MLX5E_INDIR_RQT_SIZE, profile->max_nch(mdev));
 
 	priv->params.lro_wqe_sz =
-		MLX5E_PARAMS_DEFAULT_LRO_WQE_SZ;
+		MLX5E_PARAMS_DEFAULT_LRO_WQE_SZ -
+		/* Extra room needed for build_skb */
+		MLX5_RX_HEADROOM -
+		SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
 
 	/* Initialize pflags */
 	MLX5E_SET_PRIV_FLAG(priv, MLX5E_PFLAG_RX_CQE_BASED_MODER,