realtek: dsa: Reelect primary port for a LAG

realtek: dsa: Reelect primary port for a LAG

rtl93xx hardware supports trunk fdb entries. That requires driver to
translate port-fdb entry to trunk fdb entry if the port is part of a
LAG.

There is no standard way of indicating fdb entries for bond interfaces.

One can use debugfs interface l2_table to dump all the entries stored in
the hardware. Trunk FDB entries are now displayed properly with trunk ID
and participating ports

Co-developed-by: Sven Eckelmann <se@simonwunderlich.de>
Signed-off-by: Sven Eckelmann <se@simonwunderlich.de>
Signed-off-by: Harshal Gohel <hg@simonwunderlich.de>
Link: https://github.com/openwrt/openwrt/pull/21740
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>