i40e: delete netdev after deleting napi and vectors

We've been deleting the netdev before getting around to deleting the napi
structs.  Unfortunately, we then didn't delete the napi structs because we
have a check for netdev, thus we were leaving garbage around in the system.

Change-ID: Ife540176f6c9f801147495b3f2d2ac2e61ddcc58
Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Signed-off-by: Catherine Sullivan <catherine.sullivan@intel.com>
Tested-by: Kavindya Deegala <kavindya.s.deegala@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>