rvu_nix_chan_lbk
pfvf->rx_chan_base = rvu_nix_chan_lbk(rvu, lbkid, vf);
rvu_nix_chan_lbk(rvu, lbkid, vf - 1) :
rvu_nix_chan_lbk(rvu, lbkid, vf + 1);