i40e: prep vsi_open logic for non-netdev cases

Rearrange the "if netdev" logic slightly to get ready for handling
non-netdev VSIs.

Change-ID: Ia0bfe13d4c994a2351a3c31fe725b75caeb397ee
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>