net/mlx5: Drain wq first during PCI device removal

mlx5_unload_one() is done with cleanup = true only once.

So instead of doing health wq drain inside the if(), directly do
during PCI device removal.

Signed-off-by: Parav Pandit <parav@mellanox.com>
Reviewed-by: Moshe Shemesh <moshe@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>