Merge pull request #14546 from adrianomarto/ospf6-point-to-multipoint

OSPF6 point to multipoint

diff --cc ospf6d/ospf6_interface.c
Simple merge

diff --cc ospf6d/ospf6_message.c
Simple merge

diff --cc ospf6d/ospf6_route.c
Simple merge

diff --cc ospf6d/ospf6_snmp.c
Simple merge