i40e: create a generic configure rss function

This patch renames the old pf-specific function in order to clarify
its scope. This patch also creates a more generic configure RSS
function with the old name.

This patch also creates a new more generic function to get RSS
configuration, using the appropriate method.

Change-ID: Ieddca2707b708ef19f1ebccdfd03a0a0cd63d3af
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>