[][MAC80211][hnat][Fix PPE entry clear issue]

[Description]
Fix PPE entry clear issue.

PPE has a cache memory, user has to clear the cache as well
when setting the PPE entry to INVALD state.

If without this patch, PPE might not unbind PPE entry immediately.

[Release-log]
N/A


Change-Id: If844b66f25c6563ea8cccdbc7e0633939dd78eaf
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/7202138
2 files changed