[][dts: mt7986: Add sd-card dts files and fix missing string]

[Description]
Add sd-card dts files and fix missing string

[Release-log]
N/A

Change-Id: Ic7502c325e1fd36b927dfaea7892912947628525
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/5499539
3 files changed