[][Optimize PPPQ mechanism for Panther]

[Description]
Add some strategies to optimize PPPQ mechanism:

(1) "Make rules to only allow the go-to-switch traffic
    being scheduled in QDMA PPPQ multi-queue".

(2) "Enable QDMA WFQ policy by default for either
    software path or hardware path".
    After consulting with designers, we realize that
    even if shaper rate control has already been disabled,
    the QDMA arbitration policy will still take effect
    anyway. So we ought to choose correct scheduling
    policy regardless of shaper configurations.

If without this patch, QDMA would wrongly apply SP policy
rather than WFQ in some cases.

[Release-log]
N/A

Change-Id: I54e200a0dd0b2f43bde3a038bbdfe53d8bd96172
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/5498851
4 files changed