ice: remove return variable

We were saving the return value from ice_vsi_manage_rss_lut(), but
the errors from that function are not critical so change it to
return void and remove the code that saved the value.

Signed-off-by: Paul M Stillwell Jr <paul.m.stillwell.jr@intel.com>
Tested-by: Tony Brelinski <tonyx.brelinski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>