bridge: Add support for setting bridge port attributes

Add netlink support bridge port attributes such as cost, priority, state
and flags.  This also adds support for HW mode such as VEPA or VEB.

Signed-off-by: Vlad Yasevich <vyasevic@redhat.com>
bridge: Add support for printing bridge port attributes

Output new nested bridge port attributes.

Signed-off-by: Vlad Yasevich <vyasevic@redhat.com>
man: Add documentation for the bridge link operation.

Bridge tool now supports setting and retrieving bridge port specific
link attributes.  Document what attributes are supported and what
they mean.

Signed-off-by: Vlad Yasevich <vyasevic@redhat.com>
bridge: add oneline option

Split output of 'bridge link' across multiple lines,
only show the flags if -d is set, and add --oneline option
like ip command.
ip xfrm state: Allow different selector family

Do not enforce the selector of a state to have the same address family
as the id. This makes it possible to configure inter family states.

Signed-off-by: Thomas Egerer <hakke_007@gmx.de>