[EXT] please help backporting some patches to stable release 20.11.6

[Tomasz Duszynski]

[...]

> 2ddf4b110c Tomasz Duszynski common/cnxk: allow changing PTP mode on CN10K

No backporting here. 

> 755fd7b22d  Wenxuan Wu       net/iavf: fix GTP-U extension flow
> 95af59b7ad  Yajun Wu         vdpa/mlx5: workaround VAR offset within page
> 196f35f81c  Yiding Zhou      net/iavf: fix VF reset
> 1907ce4bae  Yuan Wang        examples/vhost: fix retry logic on Rx path
> 41f9a1757f  Yuan Wang        net/virtio-user: fix socket non-blocking mode