net: dsa: lantiq_gswip: Change literal 6 to ETH_ALEN

The addr variable in gswip_port_fdb_dump() stores a mac address. Use
ETH_ALEN to make this consistent across other drivers.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Acked-by: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: Martin Schiller <ms@dev.tdt.de>
Link: https://lore.kernel.org/r/20240611135434.3180973-9-ms@dev.tdt.de


Signed-off-by: Jakub Kicinski <kuba@kernel.org>