virtio_net: Fix error unwinding of XDP initialization

In the Linux kernel, the following vulnerability has been resolved:

virtio_net: Fix error unwinding of XDP initialization

When initializing XDP in virtnet_open(), some rq xdp initialization may hit an error causing net device open failed. However, previous rqs have already initialized XDP and enabled NAPI, which is not the expected behavior. Need to roll back the previous rq initialization to avoid leaks in error unwinding of init code.

Also extract helper functions of disable and enable queue pairs. Use newly introduced disable helper function in error unwinding and virtnet_close. Use enable helper function in virtnet_open.