net: airoha: Add missing PPE configurations in airoha_ppe_hw_init()

Add the following PPE configuration in airoha_ppe_hw_init routine:
- 6RD hw offloading is currently not supported by Netfilter flowtable.
  Disable explicitly PPE 6RD offloading in order to prevent PPE to learn
  6RD flows and eventually interrupt the traffic.
- Add missing PPE bind rate configuration for L3 and L2 traffic.
  PPE bind rate configuration specifies the pps threshold to move a PPE
  entry state from UNBIND to BIND. Without this configuration this value
  is random.
- Set ageing thresholds to the values used in the vendor SDK in order to
  improve connection stability under load and avoid packet loss caused by
  fast aging.

Fixes: 00a7678310fe3 ("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/20260412-airoha_ppe_hw_init-missing-bits-v1-1-06ac670819e3@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>