hv_netvsc: Fix the list processing for network change event

RNDIS_STATUS_NETWORK_CHANGE event is handled as two "half events" --
media disconnect & connect. The second half should be added to the list
head, not to the tail. So all events are processed in normal order.

Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Reviewed-by: K. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>