This patch adds handling for the ALLOW_NEW_SOURCES IGMPv3/MLDv2 report
types and limits them only when multicast_igmp_version == 3 or
multicast_mld_version == 2 respectively. Now that IGMPv3/MLDv2 handling
functions will be managing timers we need to delay their activation, thus
a new argument is added which controls if the timer should be updated.
We also disable host IGMPv3/MLDv2 handling as it's not yet implemented and
could cause inconsistent group state, the host can only join a group as
EXCLUDE {} or leave it.

v4: rename update_timer to igmpv2_mldv1 and use the passed value from
    br_multicast_add_group's callers
v3: Add IPv6/MLDv2 support
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>