i40e: add constraints for accessing veb array

Add veb array access boundary checks.
Ensure veb array index is smaller than I40E_MAX_VEB.

Signed-off-by: Piotr Kwapulinski <piotr.kwapulinski@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>