net: dsa: {e}dsa: set offload_fwd_mark on received packets

The software bridge needs to know if a packet has already been bridged
by hardware offload to ports in the same hardware offload, in order
that it does not re-flood them, causing duplicates. This is
particularly true for broadcast and multicast traffic which the host
has requested.

By setting offload_fwd_mark in the skb the bridge will only flood to
ports in other offloads and other netifs. Set this flag in the DSA and
EDSA tag driver.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>