i40e: factor out re-enable functions for ATR and SB

A future patch needs to expand on the logic for re-enabling ATR. Doing
so would cause some code to break the 80-character line limit.

To reduce the level of indentation, factor out helper functions for
re-enabling ATR and SB rules.

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>