switchdev: add bridge ageing_time attribute

Setting the stage to push bridge-level attributes down to port driver so
hardware can be programmed accordingly.  Bridge-level attribute example is
ageing_time.  This is a per-bridge attribute, not a per-bridge-port attr.
Signed-off-by: NScott Feldman <sfeldma@gmail.com>
Acked-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/net/switchdev.h

@@ -43,6 +43,7 @@ enum switchdev_attr_id {
 	SWITCHDEV_ATTR_ID_PORT_PARENT_ID,
 	SWITCHDEV_ATTR_ID_PORT_STP_STATE,
 	SWITCHDEV_ATTR_ID_PORT_BRIDGE_FLAGS,
+	SWITCHDEV_ATTR_ID_BRIDGE_AGEING_TIME,
 };
 
 struct switchdev_attr {
@@ -52,6 +53,7 @@ struct switchdev_attr {
 		struct netdev_phys_item_id ppid;	/* PORT_PARENT_ID */
 		u8 stp_state;				/* PORT_STP_STATE */
 		unsigned long brport_flags;		/* PORT_BRIDGE_FLAGS */
+		u32 ageing_time;			/* BRIDGE_AGEING_TIME */
 	} u;
 };