[][SW framework][common][snfi][Add MT7981 support for mtk-snand driver]

[Description]
Add MT7981 support for mtk-snand driver

[Release-log]
N/A

Change-Id: I149d9640d61a459895f35cf04888e8c96741f4d8
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/6386874
3 files changed