net: bridge: Fix improper taking over HW learned FDB

net: bridge: Fix improper taking over HW learned FDB

Commit 841866424858 ("net: bridge: allow SW learn to take over HW fdb
entries") added the ability to "take over an entry which was previously
learned via HW when it shows up from a SW port".

However, if an entry was learned via HW and then a control packet
(e.g., ARP request) was trapped to the CPU, the bridge driver will
update the entry and remove the externally learned flag, although the
entry is still present in HW. Instead, only clear the externally learned
flag in case of roaming.

Fixes: 841866424858 ("net: bridge: allow SW learn to take over HW fdb entries")
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Arkadi Sharashevsky <arkadis@mellanox.com>
Cc: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Acked-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>