dt-bindings: usb: Add binding for WCH CH334/CH335 hub controller

dt-bindings: usb: Add binding for WCH CH334/CH335 hub controller

The WCH CH334/CH335[0] are USB2.0 protocol compliant 4-port USB HUB
controller chips, supporting USB2.0 high-speed and full-speed for
upstream ports, and USB2.0 high-speed 480Mbps, full-speed 12Mbps and
low-speed 1.5Mbps for downstream ports, supporting not only low-cost STT
mode (single TT schedules 4 downstream ports in time share), but also
supports high performance MTT mode (4 TTs each corresponding to 1 port,
concurrent processing).

Add a device tree binding for it.

[0]: https://www.wch-ic.com/downloads/CH334DS1_PDF.html

Signed-off-by: Chaoyi Chen <chaoyi.chen@rock-chips.com>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://patch.msgid.link/20260113095827.115-2-kernel@airkyi.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>