ksmbd: Remove redundant 'flush_workqueue()' calls

'destroy_workqueue()' already drains the queue before destroying it, so
there is no need to flush it explicitly.

Remove the redundant 'flush_workqueue()' calls.

This was generated with coccinelle:

@@
expression E;
@@
- 	flush_workqueue(E);
	destroy_workqueue(E);
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/ksmbd/ksmbd_work.c

@@ -69,7 +69,6 @@ int ksmbd_workqueue_init(void)
 
 void ksmbd_workqueue_destroy(void)
 {
-	flush_workqueue(ksmbd_wq);
 	destroy_workqueue(ksmbd_wq);
 	ksmbd_wq = NULL;
 }

fs/ksmbd/transport_rdma.c

@@ -2043,7 +2043,6 @@ int ksmbd_rdma_destroy(void)
 	smb_direct_listener.cm_id = NULL;
 
 	if (smb_direct_wq) {
-		flush_workqueue(smb_direct_wq);
 		destroy_workqueue(smb_direct_wq);
 		smb_direct_wq = NULL;
 	}