net/mlx5e: Use channel mdev reference instead of global mdev instance for coalescing

Channels can potentially have independent mdev instances. Do not refer to
the global mdev instance in the mlx5e_priv instance for channel FW
operations related to coalescing. CQ numbers that would be valid on the
channel's mdev instance may not be correctly referenced if using the
mlx5e_priv instance.

Fixes: 67936e13 ("net/mlx5e: Let channels be SD-aware")
Signed-off-by: Rahul Rameshbabu <rrameshbabu@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://lore.kernel.org/r/20240411115444.374475-5-tariqt@nvidia.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

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

@@ -589,12 +589,12 @@ static int mlx5e_get_coalesce(struct net_device *netdev,
 static void
 mlx5e_set_priv_channels_tx_coalesce(struct mlx5e_priv *priv, struct ethtool_coalesce *coal)
 {
-	struct mlx5_core_dev *mdev = priv->mdev;
 	int tc;
 	int i;
 
 	for (i = 0; i < priv->channels.num; ++i) {
 		struct mlx5e_channel *c = priv->channels.c[i];
+		struct mlx5_core_dev *mdev = c->mdev;
 
 		for (tc = 0; tc < c->num_tc; tc++) {
 			mlx5_core_modify_cq_moderation(mdev,
@@ -608,11 +608,11 @@ mlx5e_set_priv_channels_tx_coalesce(struct mlx5e_priv *priv, struct ethtool_coal
 static void
 mlx5e_set_priv_channels_rx_coalesce(struct mlx5e_priv *priv, struct ethtool_coalesce *coal)
 {
-	struct mlx5_core_dev *mdev = priv->mdev;
 	int i;
 
 	for (i = 0; i < priv->channels.num; ++i) {
 		struct mlx5e_channel *c = priv->channels.c[i];
+		struct mlx5_core_dev *mdev = c->mdev;
 
 		mlx5_core_modify_cq_moderation(mdev, &c->rq.cq.mcq,
 					       coal->rx_coalesce_usecs,