[][Refine QDMA rate control shaper when running PPPQ]

[Description]
Refactor QDMA Per-Port-Per-Queue(PPPQ) mode.
Because QDMA scheduler has 1Gbps rate limitation, the rate control
shaper must be fine-tuned when activating PPPQ mode.

[Release-log]
N/A

Change-Id: Ie7a1c6292e8e3b302deb97e2e78145ce9171cf4d
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/5355282
3 files changed