ASoC: omap-mcpdm: Mark expected switch fall-throughs

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

Addresses-Coverity-ID: 1369526 ("Missing break in switch")
Addresses-Coverity-ID: 1369529 ("Missing break in switch")
Addresses-Coverity-ID: 1451415 ("Missing break in switch")
Addresses-Coverity-ID: 115103 ("Missing break in switch")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/omap/omap-mcpdm.c

@@ -310,15 +310,19 @@ static int omap_mcpdm_dai_hw_params(struct snd_pcm_substream *substream,
 			/* up to 3 channels for capture */
 			return -EINVAL;
 		link_mask |= 1 << 4;
+		/* fall through */
 	case 4:
 		if (stream == SNDRV_PCM_STREAM_CAPTURE)
 			/* up to 3 channels for capture */
 			return -EINVAL;
 		link_mask |= 1 << 3;
+		/* fall through */
 	case 3:
 		link_mask |= 1 << 2;
+		/* fall through */
 	case 2:
 		link_mask |= 1 << 1;
+		/* fall through */
 	case 1:
 		link_mask |= 1 << 0;
 		break;