[][Refactor mt7986 dts/image to base on nand/nor model]

[Description]
Refactor mt7986 dts/image to base on nand/nor model

[Release-log]
N/A

Change-Id: I3b65a980d5513011fdd860223daff81745e9fa21
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/4641694
9 files changed