dt-bindings: soc: rockchip: add rk3588 USB3 syscon

RK3588 USB3 support requires the GRF for USB and USBDP PHY.

Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Link: https://lore.kernel.org/r/20240213163609.44930-3-sebastian.reichel@collabora.com


Signed-off-by: Heiko Stuebner <heiko@sntech.de>