[][MAC80211][hnat][Add hash index sanity check to __mtk_ppe_check_skb]

[Description]
Add hash index sanity check to __mtk_ppe_check_skb.

If without this patch, kernel will assert panic when receiving hash
index lager than MTK_PPE_ENTRIES.

[Release-log]
N/A


Change-Id: I9001a0fb612f053dd5c579cdecf944a1b02a4c9e
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/6792852
1 file changed