vmxnet3: add support for 32 Tx/Rx queues

Currently, vmxnet3 supports maximum of 8 Tx/Rx queues. With increase
in number of vcpus on a VM, to achieve better performance and utilize
idle vcpus, we need to increase the max number of queues supported.

This patch enhances vmxnet3 to support maximum of 32 Tx/Rx queues.
Increasing the Rx queues also increases the probability of distrubuting
the traffic from different flows to different queues with RSS.

Signed-off-by: Ronak Doshi <doshir@vmware.com>
Acked-by: Guolin Yang <gyang@vmware.com>
Signed-off-by: David S. Miller <davem@davemloft.net>