ASoC: tlv320aic23: remove unused variable 'tlv320aic23_rec_src'

sound/soc/codecs/tlv320aic23.c:70:29: warning:
 tlv320aic23_rec_src defined but not used [-Wunused-const-variable=]

It is never used, so can be removed.
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190815091534.57780-1-yuehaibing@huawei.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/tlv320aic23.c

@@ -67,8 +67,6 @@ static SOC_ENUM_SINGLE_DECL(rec_src_enum,
 static const struct snd_kcontrol_new tlv320aic23_rec_src_mux_controls =
 SOC_DAPM_ENUM("Input Select", rec_src_enum);
 
-static SOC_ENUM_SINGLE_DECL(tlv320aic23_rec_src,
-			    TLV320AIC23_ANLG, 2, rec_src_text);
 static SOC_ENUM_SINGLE_DECL(tlv320aic23_deemph,
 			    TLV320AIC23_DIGT, 1, deemph_text);