rockchip: rk3588-rock-5b: Drop usb-typec node from u-boot.dtsi

The usb-typec related nodes and props added in the board u-boot.dtsi
file has not yet landed in upstream Linux kernel DT, and they are not
needed for U-Boot to use the USB Type-C port in peripheral mode.

Remove superfluous usb-typec related nodes and props and replace them
with a simple dr_mode and maximum-speed prop to cleanup the board
u-boot.dtsi file.

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>