xen: Fix PV-on-HVM In the context of PV-on-HVM under Xen, the emulated nics are supposed to be unplug before the guest drivers are initialized, when the guest write to a specific IO port. Without this patch, the guest end up with two nics with the same MAC, the emulated nic and the PV nic. Signed-off-by: Anthony PERARD <anthony.perard@citrix.com> Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com>