Currently the Tx and Rx ring count for representors is fixed.
It does not consider the number of rings created for the parent
function. And that can cause issues not only during initialization
but while running traffic.
Instead check the number of rings created for the parent function
while configuring the ring resources for representors.
In some cases VF rep ring init may happen before the parent function's
rings have been setup. And this can cause representor ring count to be
configured as 0. In such cases, initialize the VF representor
ring count to 8.