ASoC: tlv320aic3x: Change Class-D amplifier gain control name

ALSA mixers cannot classify this "Class-D Amplifier Gain" speaker output
gain control as a playback control. Fix this by changing the name as
"Class-D Playback Volume".
Signed-off-by: NJarkko Nikula <jarkko.nikula@bitmer.com>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

sound/soc/codecs/tlv320aic3x.c

@@ -368,7 +368,7 @@ static const struct snd_kcontrol_new aic3x_snd_controls[] = {
 static DECLARE_TLV_DB_SCALE(classd_amp_tlv, 0, 600, 0);
 
 static const struct snd_kcontrol_new aic3x_classd_amp_gain_ctrl =
-	SOC_DOUBLE_TLV("Class-D Amplifier Gain", CLASSD_CTRL, 6, 4, 3, 0, classd_amp_tlv);
+	SOC_DOUBLE_TLV("Class-D Playback Volume", CLASSD_CTRL, 6, 4, 3, 0, classd_amp_tlv);
 
 /* Left DAC Mux */
 static const struct snd_kcontrol_new aic3x_left_dac_mux_controls =