arm64: dts: rockchip: Add RK3576 SAI nodes

arm64: dts: rockchip: Add RK3576 SAI nodes

The RK3576 SoC has 10 SAI controllers in total. Five of them are in the
video output power domains, and are used for digital audio output along
with the video signal of those, e.g. HDMI audio.

The other five, SAI0 through SAI4, are exposed externally. SAI0 and SAI1
are capable of 8-channel audio, whereas SAI2, SAI3 and SAI4 are limited
to two channels. These five are in the audio power domain.

Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
Link: https://lore.kernel.org/r/20250506-rk3576-sai-v4-1-a8b5f5733ceb@collabora.com
Signed-off-by: Heiko Stuebner <heiko@sntech.de>