ASoC: meson: aiu: add audio output dt-bindings

Add the dt-bindings and documentation of the AIU audio controller.
This component provides most of the audio outputs found on the Amlogic
Gx SoC family.

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Link: https://lore.kernel.org/r/20200213155159.3235792-4-jbrunet@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

include/dt-bindings/sound/meson-aiu.h

@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __DT_MESON_AIU_H
+#define __DT_MESON_AIU_H
+
+#define AIU_CPU			0
+#define AIU_HDMI		1
+#define AIU_ACODEC		2
+
+#define CPU_I2S_FIFO		0
+#define CPU_SPDIF_FIFO		1
+#define CPU_I2S_ENCODER		2
+#define CPU_SPDIF_ENCODER	3
+
+#define CTRL_I2S		0
+#define CTRL_PCM		1
+#define CTRL_OUT		2
+
+#endif /* __DT_MESON_AIU_H */