local-node: periodically send link-measurement requests

Send link-measurement requests to every supporting local-sta in order to
acquire information to assess the link-quality bi-directional.

The link-measurement request is sent each configurable interval. It can
be disabled by configuring the interval to 0.

Signed-off-by: David Bauer <mail@david-bauer.net>

node.h

@@ -70,6 +70,8 @@ struct usteer_local_node {
 		bool req_pending;
 		bool status_complete;
 	} netifd;
+
+	unsigned int link_measurement_tries;
 };
 
 struct interface;