net/mlx5e: Fix use-after-free in mlx5e_tx_reporter_timeout_recover

net/mlx5e: Fix use-after-free in mlx5e_tx_reporter_timeout_recover

mlx5e_tx_reporter_timeout_recover() accesses sq->netdev after
mlx5e_safe_reopen_channels() has torn down and freed the channel (and
its embedded SQs). Replace the three sq->netdev references with
priv->netdev which is safe because priv outlives channel teardown.

The netdev_err() call already used priv->netdev for this reason; make
the trylock/unlock and health_channel_eq_recover calls consistent.

This fixes the following KASAN splat:

  BUG: KASAN: use-after-free in mlx5e_tx_reporter_timeout_recover+0x1dd/0x360 [mlx5_core]
  Read of size 8 at addr ffff889860ed0b28 by task kworker/u113:2/5277

  Call Trace:
   mlx5e_tx_reporter_timeout_recover+0x1dd/0x360 [mlx5_core]
   devlink_health_reporter_recover+0xa2/0x150
   devlink_health_report+0x254/0x7c0
   mlx5e_reporter_tx_timeout+0x297/0x380 [mlx5_core]
   mlx5e_tx_timeout_work+0x109/0x170 [mlx5_core]
   process_one_work+0x677/0xf20
   worker_thread+0x51f/0xd90
   kthread+0x3a5/0x810
   ret_from_fork+0x208/0x400
   ret_from_fork_asm+0x1a/0x30

Fixes: 83ac0304a2d7 ("net/mlx5e: Fix deadlocks between devlink and netdev instance locks")
Cc: stable@vger.kernel.org
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Matt Fleming <mfleming@cloudflare.com>
Link: https://patch.msgid.link/20260513112226.140512-1-matt@readmodwrite.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>