net: ethernet: qualcomm: Initialize PPE L2 bridge settings

net: ethernet: qualcomm: Initialize PPE L2 bridge settings

Initialize the L2 bridge settings for the PPE ports to only enable
L2 frame forwarding between CPU port and PPE Ethernet ports.

The per-port L2 bridge settings are initialized as follows:
For PPE CPU port, the PPE bridge TX is enabled and FDB learning is
disabled. For PPE physical ports, the default L2 forwarding action
is initialized to forward to CPU port only.

L2/FDB learning and forwarding will not be enabled for PPE physical
ports yet, since the port's VSI (Virtual Switch Instance) and VSI
membership are not yet configured, which are required for FDB
forwarding. The VSI and FDB forwarding will later be enabled when
switchdev is enabled.

Signed-off-by: Lei Wei <quic_leiwei@quicinc.com>
Signed-off-by: Luo Jie <quic_luoj@quicinc.com>
Link: https://patch.msgid.link/20250818-qcom_ipq_ppe-v8-12-1d4ff641fce9@quicinc.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>