vmxnet3: add latency measurement support in vmxnet3

This patch enhances vmxnet3 to support latency measurement.
This support will help to track the latency in packet processing
between guest virtual nic driver and host. For this purpose, we
introduce a new timestamp ring in vmxnet3 which will be per Tx/Rx
queue. This ring will be used to carry timestamp of the packets
which will be used to calculate the latency.

User can enable latency measurement using realtime knob in vnic
setting in VCenter.

Signed-off-by: Ronak Doshi <ronak.doshi@broadcom.com>
Acked-by: Guolin Yang <guolin.yang@broadcom.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20240531193050.4132-3-ronak.doshi@broadcom.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>