ASoC: topology: Add definitions for mclk_direction values

Current comment makes not clear the direction of mclk. Previously, similar
description caused a misunderstanding for bclk_master and fsync_master.

This commit solves the potential confusion the same way it is solved for
bclk_master and fsync_master.

Signed-off-by: Kirill Marinushkin <k.marinushkin@gmail.com>
Acked-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Mark Brown <broonie@kernel.org>
Cc: Pan Xiuli <xiuli.pan@linux.intel.com>
Cc: Liam Girdwood <liam.r.girdwood@linux.intel.com>
Cc: linux-kernel@vger.kernel.org
Cc: alsa-devel@alsa-project.org
Signed-off-by: Mark Brown <broonie@kernel.org>

include/uapi/sound/asoc.h

@@ -144,6 +144,10 @@
 #define SND_SOC_TPLG_DAI_CLK_GATE_GATED	1
 #define SND_SOC_TPLG_DAI_CLK_GATE_CONT		2
 
+/* DAI mclk_direction */
+#define SND_SOC_TPLG_MCLK_CO            0 /* for codec, mclk is output */
+#define SND_SOC_TPLG_MCLK_CI            1 /* for codec, mclk is input */
+
 /* DAI physical PCM data formats.
  * Add new formats to the end of the list.
  */
@@ -334,7 +338,7 @@ struct snd_soc_tplg_hw_config {
 	__u8 invert_fsync;	/* 1 for inverted frame clock, 0 for normal */
 	__u8 bclk_master;	/* SND_SOC_TPLG_BCLK_ value */
 	__u8 fsync_master;	/* SND_SOC_TPLG_FSYNC_ value */
-	__u8 mclk_direction;    /* 0 for input, 1 for output */
+	__u8 mclk_direction;    /* SND_SOC_TPLG_MCLK_ value */
 	__le16 reserved;	/* for 32bit alignment */
 	__le32 mclk_rate;	/* MCLK or SYSCLK freqency in Hz */
 	__le32 bclk_rate;	/* BCLK freqency in Hz */