i40evf: remove unnecessary __packed

This is similar to 'commit 9588397d ("i40e: remove unnecessary
__packed")' to avoid unaligned access.

Signed-off-by: Tushar Dave <tushar.n.dave@oracle.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>