io_uring: refactor io_async_cancel()

Remove extra tctx==NULL checks that are already done by
io_async_cancel_one().
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/70c2a8b958d942e86958a28af0452966ce1095b0.1617287883.git.asml.silence@gmail.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

fs/io_uring.c

@@ -5824,8 +5824,6 @@ static int io_async_cancel(struct io_kiocb *req, unsigned int issue_flags)
 	list_for_each_entry(node, &ctx->tctx_list, ctx_node) {
 		struct io_uring_task *tctx = node->task->io_uring;
 
-		if (!tctx || !tctx->io_wq)
-			continue;
 		ret = io_async_cancel_one(tctx, req->cancel.addr, ctx);
 		if (ret != -ENOENT)
 			break;