net/tls: Remove redundant workqueue flush before destroy

destroy_workqueue() safely destroys the workqueue after draining it.
No need for the explicit call to flush_workqueue(). Remove it.
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://lore.kernel.org/r/20220801112444.26175-1-tariqt@nvidia.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

net/tls/tls_device.c

@@ -1449,7 +1449,6 @@ int __init tls_device_init(void)
 void __exit tls_device_cleanup(void)
 {
 	unregister_netdevice_notifier(&tls_dev_notifier);
-	flush_workqueue(destruct_wq);
 	destroy_workqueue(destruct_wq);
 	clean_acked_data_flush();
 }