ASoC: tlv320dac31xx: mark expected switch fall-through

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

Addresses-Coverity-ID: 1195220
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/tlv320aic31xx.c

@@ -929,7 +929,7 @@ static int aic31xx_set_dai_fmt(struct snd_soc_dai *codec_dai,
 	case SND_SOC_DAIFMT_I2S:
 		break;
 	case SND_SOC_DAIFMT_DSP_A:
-		dsp_a_val = 0x1;
+		dsp_a_val = 0x1; /* fall through */
 	case SND_SOC_DAIFMT_DSP_B:
 		/* NOTE: BCLKINV bit value 1 equas NB and 0 equals IB */
 		switch (fmt & SND_SOC_DAIFMT_INV_MASK) {