Add all essential MTK SDHC properties to support the new mmc-mtk
driver. Since this driver relies on power regulators, we also
need to enable this feature for MT7620, just like MT762{1,8}.
Signed-off-by: Shiji Yang <yangshiji66@qq.com>
Co-authored-by: John Thomson <git@johnthomson.fastmail.com.au>
338f40b3b4