arm64: dts: mediatek: mt6795: Create soc bus node and move mmio devices

MMIO devices should be inside of a soc bus node, as it's done for the
vast majority of ARM64 devicetrees, and for almost all MTK devicetrees.
Create a simple-bus soc node and move all devices with a MMIO address
space in there.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20220609112303.117928-2-angelogioacchino.delregno@collabora.com


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