net: airoha: Add wlan flowtable TX offload

net: airoha: Add wlan flowtable TX offload

[ Upstream commit a8bdd935d1ddb7186358fb60ffe84253e85340c8 ]

Introduce support to offload the traffic received on the ethernet NIC
and forwarded to the wireless one using HW Packet Processor Engine (PPE)
capabilities.

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://patch.msgid.link/20250814-airoha-en7581-wlan-tx-offload-v1-1-72e0a312003e@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Stable-dep-of: 8e0a754b0836 ("net: airoha: Do not loopback traffic to GDM2 if it is available on the device")
Signed-off-by: Sasha Levin <sashal@kernel.org>