ASoC: dt-bindings: amlogic,gx-sound-card: document clocks property

ASoC: dt-bindings: amlogic,gx-sound-card: document clocks property

The sound card design is based on reference PLL frequencies that
are the root of all clock rates calculations.

Today, those frequencies are currently specified in DT via assigned-clocks,
because they correspond to the basic audio use-case.

It makes no sense to setup clock rates for a sound card without
referencing the clocks for the sound card, mainly because at
some point more complex audio use cases will be supported
and those root rates would need to change.

To solve this situation, let's legitimize the presence of assigned-clocks
in the sound card by documenting those clocks, as it describes a true
dependency of the sound card and paths the way of more complex
audio uses-cases involving those root frequencies.

Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://patch.msgid.link/20240828-topic-amlogic-upstream-bindings-fixes-audio-snd-card-v2-2-58159abf0779@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>