null: add virtual RSS configuration
null: add virtual RSS configuration

This implementation allows to set and read RSS configuration for null
device, and is used to validate right values propagation over the slaves,
in test units for dynamic RSS configuration for bonding.

Signed-off-by: Tomasz Kulasek <2fc2c8542a2a68801ce1aaca56eae5adf14485ae@intel.com>
Acked-by: Tetsuya Mukawa <b347a9f5840345582b30d055e1e99ac6ac7bce3c@igel.co.jp>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk