i40e: acknowledge VFLR when disabling SR-IOV

i40e: acknowledge VFLR when disabling SR-IOV

When SR-IOV is disabled, the (now nonexistent) virtual function
devices undergo a VFLR event. We don't need to handle this event
because the VFs are gone, but we do need to tell the HW that they are
complete. This fixes an issue with a phantom VFLR and broken VFs when
SR-IOV is re-enabled.

Change-Id: I7580b49ded0158172a85b14661ec212af77000c8
Signed-off-by: Mitch Williams <mitch.a.williams@intel.com>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Sibai Li <sibai.li@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>