arm64: dts: rockchip: add the i2s3_2ch node to rk356x

Add the two-channel I2S controller I2S3_2CH to the rk356x device tree.

Signed-off-by: Michael Riesch <michael.riesch@wolfvision.net>
Link: https://lore.kernel.org/r/20220131153457.391460-1-michael.riesch@wolfvision.net


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