bridge: netlink: export port's designated cost and port

Add IFLA_BRPORT_DESIGNATED_(COST|PORT) to allow getting the port's
designated cost and port respectively via netlink.

Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index e891c32..837caf9 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -294,6 +294,8 @@
 	IFLA_BRPORT_PROXYARP_WIFI, /* proxy ARP for Wi-Fi */
 	IFLA_BRPORT_ROOT_ID,	/* designated root */
 	IFLA_BRPORT_BRIDGE_ID,	/* designated bridge */
+	IFLA_BRPORT_DESIGNATED_PORT,
+	IFLA_BRPORT_DESIGNATED_COST,
 	__IFLA_BRPORT_MAX
 };
 #define IFLA_BRPORT_MAX (__IFLA_BRPORT_MAX - 1)