Add a new VLAN attribute that allows user space to set the neighbor
suppression state of the port VLAN. Example:

 # bridge -d -j -p vlan show dev swp1 vid 10 | jq '.[]["vlans"][]["neigh_suppress"]'
 false
 # bridge vlan set vid 10 dev swp1 neigh_suppress on
 # bridge -d -j -p vlan show dev swp1 vid 10 | jq '.[]["vlans"][]["neigh_suppress"]'
 true
 # bridge vlan set vid 10 dev swp1 neigh_suppress off
 # bridge -d -j -p vlan show dev swp1 vid 10 | jq '.[]["vlans"][]["neigh_suppress"]'
 false

 # bridge vlan set vid 10 dev br0 neigh_suppress on
 Error: bridge: Can't set neigh_suppress for non-port vlans.
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: David S. Miller <davem@davemloft.net>