Merge branch '2022-09-23-add-mediatek-mt7986-support' into next

To quote the author:
This patch series add support for MediaTek MT7981/MT7986 SoCs with their
reference boards and related drivers.

This patch series add basic boot support on eMMC/SD/SPI-NOR/SPI-NAND for
these boards. The clock, pinctrl drivers and the SoC initializaton code
are also included.

Product spec for MT7986:
https://www.mediatek.com/products/home-networking/mediatek-filogic-830