arm64: dts: mediatek: mt8195: Add MTU3 nodes and correctly describe USB

The MT8195 SoC has four USB controllers: only one is a direct path to
a XHCI controller, while the other three (0, 2 and 3) are behind the
MTU3 DRD controller instead!

Add the missing MTU3 nodes, default disabled, for controllers 0, 2 and
3 and move the related XHCI nodes to be children of their MTU3 DRD to
correctly describe the SoC.

In order to retain USB functionality on all of the MT8195 and MT8395
boards, also move the vusb33 supply and enable the relevant MTU3 nodes
with special attention to the MT8195 Cherry Chromebook, where it was
necessary to set the dr_mode of all MTU3 controllers to host to avoid
interfering with the EC performing DRD on its own.

Tested-by: Chen-Yu Tsai <wenst@chromium.org>
Link: https://lore.kernel.org/r/20240115084336.938426-1-angelogioacchino.delregno@collabora.com


Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>