ASoC: ak4642: tidyup DAPM route for playback

It needs DAC -> Playback route instead of direct settings via
SND_SOC_DAPM_DAC. otherwise, it can't find correct path if
sound card used prefix name

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/ak4642.c

@@ -187,7 +187,7 @@ static const struct snd_soc_dapm_widget ak4642_dapm_widgets[] = {
 			   ARRAY_SIZE(ak4642_lout_mixer_controls)),
 
 	/* DAC */
-	SND_SOC_DAPM_DAC("DAC", "HiFi Playback", PW_MGMT1, 2, 0),
+	SND_SOC_DAPM_DAC("DAC", NULL, PW_MGMT1, 2, 0),
 };
 
 static const struct snd_soc_dapm_route ak4642_intercon[] = {
@@ -205,6 +205,8 @@ static const struct snd_soc_dapm_route ak4642_intercon[] = {
 	{"DACH", NULL, "DAC"},
 
 	{"LINEOUT Mixer", "DACL", "DAC"},
+
+	{ "DAC", NULL, "Playback" },
 };
 
 /*