[XFRM] STATE: Add Mobile IPv6 route optimization protocols to netlink interface.

Add Mobile IPv6 route optimization protocols to netlink interface.
Route optimization states carry care-of address.
Based on MIPL2 kernel patch.

Signed-off-by: Masahide NAKAMURA <nakam@linux-ipv6.org>
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>