net: airoha: Initialize PPE UPDMEM source-mac table

UPDMEM source-mac table is a key-value map used to store devices mac
addresses according to the port identifier. UPDMEM source mac table is
used during IPv6 traffic hw acceleration since PPE entries, for space
constraints, do not contain the full source mac address but just the
identifier in the UPDMEM source-mac table.
Configure UPDMEM source-mac table with device mac addresses and set
the source-mac ID field for PPE IPv6 entries in order to select the
proper device mac address as source mac for L3 IPv6 hw accelerated traffic.

Fixes: 00a76783 ("net: airoha: Introduce flowtable offload support")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250602-airoha-flowtable-ipv6-fix-v2-1-3287f8b55214@kernel.org


Signed-off-by: Paolo Abeni <pabeni@redhat.com>