switchdev: Add support for flood control

Allow devices supporting this feature to control the flooding of unknown
unicast traffic, by making switchdev infrastructure propagate this setting
to the switch driver.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/Documentation/networking/switchdev.txt b/Documentation/networking/switchdev.txt
index 0714fe5..ce510e1 100644
--- a/Documentation/networking/switchdev.txt
+++ b/Documentation/networking/switchdev.txt
@@ -298,6 +298,9 @@
 of ports scale in the L2 domain as the device is much more efficient at
 flooding packets that software.
 
+If supported by the device, flood control can be offloaded to it, preventing
+certain netdevs from flooding unicast traffic for which there is no FDB entry.
+
 IGMP Snooping
 ^^^^^^^^^^^^^