arm64: dts: mt8192: add nor_flash device node

add nor_flash device node

Signed-off-by: bayi cheng <bayi.cheng@mediatek.com>
Link: https://lore.kernel.org/r/1608697379-22025-1-git-send-email-bayi.cheng@mediatek.com


Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>