arm64: dts: mt8173: fix some indentation

Fix indentation nits to make mt8173.dtsi more consistent.

Signed-off-by: Eddie Huang <eddie.huang@mediatek.com>
Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>