i40e: cleanup whitespace for some ethtool stat definitions

A future patch is going to refactor some of the ethtool statistic code.
To keep the patches easy to review, cleanup some of the indentation used
for macro definitions first.
Signed-off-by: NJacob Keller <jacob.e.keller@intel.com>
Tested-by: NAndrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>