arm64: dts: rockchip: add dsi controller nodes on rk3588

The RK3588 comes with two DSI2 controllers based on a new Synopsis IP.
Add the necessary nodes for them.

Signed-off-by: Heiko Stuebner <heiko.stuebner@cherry.de>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Tested-by: Sebastian Reichel <sebastian.reichel@collabora.com> # RK3588 EVB1
Link: https://lore.kernel.org/r/20250226140942.3825223-3-heiko@sntech.de


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