net/thunderx: remove private data to ethdev link

net/thunderx: remove private data to ethdev link

In case of the multiprocess mode a shared nicvf struct between processes
cannot point with the eth_dev pointer to master device, therefore remove it
along with references to it refactoring the code where needed.

This change fixes multiprocess issues detected in stats.

Fixes: 7413feee662d ("net/thunderx: add device start/stop and close")
Signed-off-by: Maciej Czekaj <maciej.czekaj@caviumnetworks.com>
Signed-off-by: Kamil Rytarowski <kamil.rytarowski@caviumnetworks.com>
Signed-off-by: Zyta Szpak <zyta.szpak@semihalf.com>
Signed-off-by: Slawomir Rosek <slawomir.rosek@semihalf.com>
Signed-off-by: Radoslaw Biernacki <rad@semihalf.com>
Signed-off-by: Jerin Jacob <jerin.jacob@caviumnetworks.com>