iplink_bridge: Add no_linklocal_learn option support

iplink_bridge: Add no_linklocal_learn option support

Kernel commit 70e4272b4c81 ("net: bridge: add no_linklocal_learn bool
option") added the no_linklocal_learn bridge option that can be set via
sysfs or netlink.

Add iproute2 support, allowing it to query and set the option via
netlink.

The option is useful, for example, in scenarios where we want the bridge
to be able to refresh dynamic FDB entries that were added by user space
and are pointing to locked bridge ports, but do not want the bridge to
populate its FDB from EAPOL frames used for authentication.

Example:

 $ ip -j -d link show dev br0 | jq ".[][\"linkinfo\"][\"info_data\"][\"no_linklocal_learn\"]"
 0
 $ cat /sys/class/net/br0/bridge/no_linklocal_learn
 0

 # ip link set dev br0 type bridge no_linklocal_learn 1

 $ ip -j -d link show dev br0 | jq ".[][\"linkinfo\"][\"info_data\"][\"no_linklocal_learn\"]"
 1
 $ cat /sys/class/net/br0/bridge/no_linklocal_learn
 1

 # ip link set dev br0 type bridge no_linklocal_learn 0

 $ ip -j -d link show dev br0 | jq ".[][\"linkinfo\"][\"info_data\"][\"no_linklocal_learn\"]"
 0
 $ cat /sys/class/net/br0/bridge/no_linklocal_learn
 0

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David Ahern <dsahern@kernel.org>