i40evf: remove flags that are never used

These flags were defined, but there is no use within the driver code, so
we don't need to keep them.

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>