ice: Fix persistent failure in ice_get_rxfh

ice: Fix persistent failure in ice_get_rxfh

Several ioctl functions have the ability to call ice_get_rxfh, however
all of these ioctl functions do not provide all of the expected
information in ethtool_rxfh_param. For example, ethtool_get_rxfh_indir does
not provide an rss_key. This previously caused ethtool_get_rxfh_indir to
always fail with -EINVAL.

This change draws inspiration from i40e_get_rss to handle this
situation, by only calling the appropriate rss helpers when the
necessary information has been provided via ethtool_rxfh_param.

Fixes: b66a972abb6b ("ice: Refactor ice_set/get_rss into LUT and key specific functions")
Signed-off-by: Cody Haas <chaas@riotgames.com>
Closes: https://lore.kernel.org/intel-wired-lan/CAH7f-UKkJV8MLY7zCdgCrGE55whRhbGAXvgkDnwgiZ9gUZT7_w@mail.gmail.com/
Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Tested-by: Rinitha S <sx.rinitha@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>