ice: Implement ethtool hook for RSS switch

This patch implements ethtool hook for enabling/disabling
RSS. While disabling RSS, the LUT should be cleared. And
the LUT should be reconfigured while enabling RSS.

Signed-off-by: Md Fahad Iqbal Polash <md.fahad.iqbal.polash@intel.com>
Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>