[][kernel][mt7988][PMIC][Fix missing cpu frequency and PMIC devicetree nodes]

[Description]
Fix missing cpu frequency and PMIC devicetree nodes.

Without this patch, cpu only works on frequency 1.5ghz,
and cannot be modified.

[Release-log]
N/A

Change-Id: I057c1a13763ac99aae5a721668c803a176721518
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/8891433
9 files changed