[][MAC80211][wifi6][mt76][Add per-band token limits and debugfs]

[Description]
Add a threshold for per-band token count.
  The band0/1 use the same token pool so a band cannot transmit if
  the other band occupy too many tokens. With this patch, we can
  prevent a band from interfering with the other band.
Add debugfs knob to show per band token count

[Release-log]
N/A

Change-Id: Iffe02b57e4f9110cf964230c3cba736ad36d2c02
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/8668370
3 files changed