iplink: bridge_slave: export read-only values

Export all the read-only values that get returned about a bridge port
such as the timers, the ids, designated_port and cost,
topology_change_ack and config_pending. For the bridge ids the
br_dump_bridge_id function is exported from iplink_bridge.

Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
diff --git a/ip/iplink_bridge.c b/ip/iplink_bridge.c
index 1b666f0..79f15ef 100644
--- a/ip/iplink_bridge.c
+++ b/ip/iplink_bridge.c
@@ -60,8 +60,7 @@
 	print_explain(stderr);
 }
 
-static void br_dump_bridge_id(const struct ifla_bridge_id *id, char *buf,
-			      size_t len)
+void br_dump_bridge_id(const struct ifla_bridge_id *id, char *buf, size_t len)
 {
 	char eaddr[32];