renamed MLD-related function names from "mld6_..." to "mld_..."; mld doesn't need '6' suffix, since it's dedicated for IPv6.
renamed MLD-related function names from "mld6_..." to "mld_...";
mld doesn't need '6' suffix, since it's dedicated for IPv6.

MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame