openvswitch: use alias for genetlink family names

When userspace tries to create datapaths and the module is not loaded,
it will simply fail. With this patch, the module will be automatically
loaded.

Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@redhat.com>
Acked-by: Pravin B Shelar <pshelar@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>