The value of vRtrMldIfMaxGroups specifies the maximum number of groups
for which the MLD can have local receiver information based on received
MLD reports on this interface. When this configuration is changed
dynamically to a value lower than currently accepted number of groups,
the groups that are already accepted are not deleted. Only new groups
will not be allowed. When this object has a value of 0, there is no
limit to the number of groups.