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: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>