io_uring: simplify iovec freeing in io_clean_op()

We don't get REQ_F_NEED_CLEANUP for rw unless there is ->free_iovec set,
so remove the optimisation of NULL checking it inline, kfree() will take
care if that would ever be the case.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/a233dc655d3d45bd4f69b73d55a61de46d914415.1623949695.git.asml.silence@gmail.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

fs/io_uring.c

@@ -6092,7 +6092,7 @@ static void io_clean_op(struct io_kiocb *req)
 		case IORING_OP_WRITE_FIXED:
 		case IORING_OP_WRITE: {
 			struct io_async_rw *io = req->async_data;
-			if (io->free_iovec)
+
 			kfree(io->free_iovec);
 			break;
 			}