i40e/i40evf: Force a shifted '1' to be unsigned

Force a shifted '1' to be unsiged to avoid shifting a signed int

Change-ID: I688cbd082af0f2e1df548fda25847a5ca04babcf
Signed-off-by: Paul M Stillwell Jr <paul.m.stillwell.jr@intel.com>
Tested-by: Jim Young <jamesx.m.young@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>