io_uring: remove two unnecessary function declarations

__io_free_req() and io_double_put_req() aren't used before they are
defined, so we can kill these two forwards.
Signed-off-by: Jens Axboe <axboe@kernel.dk>

fs/io_uring.c

@@ -518,9 +518,7 @@ struct io_submit_state {
 
 static void io_wq_submit_work(struct io_wq_work **workptr);
 static void io_cqring_fill_event(struct io_kiocb *req, long res);
-static void __io_free_req(struct io_kiocb *req);
 static void io_put_req(struct io_kiocb *req);
-static void io_double_put_req(struct io_kiocb *req);
 static void __io_double_put_req(struct io_kiocb *req);
 static struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req);
 static void io_queue_linked_timeout(struct io_kiocb *req);