[][kernel][7988][hnat][Add 3PPE configuration to DTS files]

[Description]
Add 3PPE configuration to DTS files

Change the maximum PPE number configuration from 1(default) to 3.

Without this patch, the RFC2544(64B packet test) would not
reach the line rate because of the limited PPE transfer capability.

[Release-log]
N/A


Change-Id: I46f7968257035ed792b35b5c1f51049aab0524cc
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/8570875
24 files changed