net: bridge: vlan: notify when global options change

Add support for global options notifications. They use only RTM_NEWVLAN
since global options can only be set and are contained in a separate
vlan global options attribute. Notifications are compressed in ranges
where possible, i.e. the sequential vlan options are equal.

Signed-off-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>