net/mlx5: Serialize module cleanup with reload and remove

[ Upstream commit 8f0d1451 ]

Currently, remove and reload flows can run in parallel to module cleanup.
This design is error prone. For example: aux_drivers callbacks are called
from both cleanup and remove flows with different lockings, which can
cause a deadlock[1].
Hence, serialize module cleanup with reload and remove.

[1]
       cleanup                        remove
       -------                        ------
   auxiliary_driver_unregister();
                                     devl_lock()
                                      auxiliary_device_delete(mlx5e_aux)
    device_lock(mlx5e_aux)
     devl_lock()
                                       device_lock(mlx5e_aux)

Fixes: 912cebf4

 ("net/mlx5e: Connect ethernet part to auxiliary bus")
Signed-off-by: Shay Drory <shayd@nvidia.com>
Reviewed-by: Moshe Shemesh <moshe@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>