ASoC: hdmi-codec: Add iec958 controls

The IEC958 status bits can be exposed and modified by the userspace
through dedicated ALSA controls.

This patch implements those controls for the hdmi-codec driver. It
relies on a default value being setup at probe time that can later be
overridden by the control put.

The hw_params callback is then called with a buffer filled with the
proper bits for the current parameters being passed on so the underlying
driver can just reuse those bits as is.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Acked-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20210525132354.297468-5-maxime@cerno.tech