net/vmxnet3: add v4 boot and guest UDP RSS config

net/vmxnet3: add v4 boot and guest UDP RSS config

This patch introduces:
- VMxnet3 v4 negotiation and,
- entirely guest-driven UDP RSS support.

VMxnet3 v3 already has UDP RSS support, however it
depends on hypervisor provisioning on the VM through
ESX specific flags, which are not transparent or known
to the guest later on.

Vmxnet3 v4 introduces a new API transaction which allows
configuring RSS entirely from the guest. This API must be
invoked after device shared mem region is initialized.

IPv4 ESP RSS (SPI based) is also available, but currently
there are no ESP RSS definitions on rte_eth layer to
handle that.

Signed-off-by: Eduard Serra <eserra@vmware.com>
Acked-by: Yong Wang <yongwang@vmware.com>