Enable I2S support for RK3588/RK3588S SoCs

Merge series from Cristian Ciocaltea <cristian.ciocaltea@collabora.com>:

There are five I2S/PCM/TDM controllers and two I2S/PCM controllers embedded
in the RK3588 and RK3588S SoCs. Furthermore, RK3588 provides four additional
I2S/PCM/TDM controllers.

This patch series adds the required device tree nodes to support all the above.

Additionally, it enables analog audio support for the Rock 5B SBC, which has
been used to test both audio playback and recording.