Add checks for DT graph bindings. These checks check node names,
unit-addresses and link connections on ports, port, and endpoint nodes.
The graph nodes are matched by finding nodes named 'endpoint' or with a
'remote-endpoint' property. We can't match on 'ports' or 'port' nodes
because those names are used for non-graph nodes. While the graph nodes
aren't really buses, using the bus pointer to tag matched nodes is
convenient.
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>