please help backporting some patches to stable release 19.11.11

[Ding, Xuan]

Hi Christian,

The two fix patches from mine aimed at DPDK version after 19.11. So they only need to be backported in 20.11.
04bcc80204  Xuan Ding        net/virtio: fix indirect descriptor reconnection
ad6f01945a  Xuan Ding        net/virtio: fix avail descriptor ID

Thanks for your reminder.

Regards,
Xuan