vmxnet3: Make ethtool handlers multiqueue aware

Show per-queue stats in ethtool -S output for vmxnet3 interface. Register dump
of ethtool should dump registers for all tx and rx queues.

Signed-off-by: Shreyas N Bhatewara <sbhatewara@vmware.com>
Signed-off-by: David S. Miller <davem@davemloft.net>