ARM: dts: rockchip: rk3588-rock-5b-u-boot: add USB3 support

ARM: dts: rockchip: rk3588-rock-5b-u-boot: add USB3 support

Enable the USB3.0 host node, and gadget node.
The gadget is available through the USB type C connector on the board.
The connector is tied to a Fairchild fusb302b device, which currently
does not have a driver in U-boot, but the node is here for correct
description of the board + Linux future compatibility.
It will be easier to move the node as-is when it will be available
in the DT from Linux

Signed-off-by: Eugen Hristev <eugen.hristev@collabora.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>