i40e: Fix ethtool offline diagnostic with netqueues

Treat netqueues the same way we do virtual functions when someone wants to
run the ethtool offline diagnostic test.

Change-ID: Id48d2b933f1fd0db7be06305a93c6ebe3dc821f5
Signed-off-by: Greg Rose <gregory.v.rose@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>