i40e: rework the functions to configure RSS with similar parameters

Adjust the RSS configure functions so that there is a generic way to
hook to ethtool hooks.

Change-ID: If446e34fcfaf1bc3320d9d319829a095b5976e67
Signed-off-by: Helin Zhang <helin.zhang@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>