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.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>