bridge: add brport flags to dflt bridge_getlink

To allow brport device to return current brport flags set on port.  Add
returned flags to nested IFLA_PROTINFO netlink msg built in dflt getlink.
With this change, netlink msg returned for bridge_getlink contains the port's
offloaded flag settings (the port's SELF settings).

Signed-off-by: Scott Feldman <sfeldma@gmail.com>
Signed-off-by: Jiri Pirko <jiri@resnulli.us>
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new in v3
rocker: add ndo_bridge_setlnk/getlink support for learning policy

Rocker ports will use new "swdev" hwmode for bridge port offload policy.
Current supported policy settings are BR_LEARNING and BR_LEARNING_SYNC.
User can turn on/off device port FDB learning and syncing to bridge.

Signed-off-by: Scott Feldman <sfeldma@gmail.com>
Signed-off-by: Jiri Pirko <jiri@resnulli.us>
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new in v3