CIFS: Fix a memory leak when a lease break comes

This happens when we receive a lease break from a server, then
find an appropriate lease key in opened files and schedule the
oplock_break slow work. lw pointer isn't freed in this case.

Cc: <stable@vger.kernel.org>
Signed-off-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>

fs/cifs/smb2misc.c

@@ -477,6 +477,7 @@ smb2_is_valid_lease_break(char *buffer, struct TCP_Server_Info *server)
 
 				queue_work(cifsiod_wq, &cfile->oplock_break);
 
+				kfree(lw);
 				spin_unlock(&cifs_file_list_lock);
 				spin_unlock(&cifs_tcp_ses_lock);
 				return true;