io_uring/zcrx: fix leaks on failed registration

If we try to register a device-less interface like veth,
io_register_zcrx_ifq() will leak struct io_zcrx_ifq with a bunch of
resources attached to it. Fix that.

Fixes: 035af94 ("io_uring/zcrx: grab a net device")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/r/202502190532.W7NnmyiP-lkp@intel.com/
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/fbf16279dd73fa4c6df048168728355636ba5f53.1739959771.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: isilence

io_uring/zcrx.c

@@ -388,8 +388,9 @@ int io_register_zcrx_ifq(struct io_ring_ctx *ctx,
 		goto err;
 
 	ifq->dev = ifq->netdev->dev.parent;
+	ret = -EOPNOTSUPP;
 	if (!ifq->dev)
-		return -EOPNOTSUPP;
+		goto err;
 	get_device(ifq->dev);
 
 	ret = io_zcrx_map_area(ifq, ifq->area);