i40e: return correct opcode to VF

This conditional is backward, so the driver responds back to the VF with
the wrong opcode. Do the old switcheroo to fix this.

Change-ID: I384035b0fef8a3881c176de4b4672009b3400b25
Signed-off-by: Mitch Williams <mitch.a.williams@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>