ALSA: emu10k1: Mark expected switch fall-throughs

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

Notice that in this particular case, I replaced the code comment with
a proper "fall through" annotation, which is what GCC is expecting
to find.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/emu10k1/emupcm.c

@@ -778,7 +778,7 @@ static int snd_emu10k1_playback_trigger(struct snd_pcm_substream *substream,
 	case SNDRV_PCM_TRIGGER_START:
 		snd_emu10k1_playback_invalidate_cache(emu, 1, epcm->extra);	/* do we need this? */
 		snd_emu10k1_playback_invalidate_cache(emu, 0, epcm->voices[0]);
-		/* follow thru */
+		/* fall through */
 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
 	case SNDRV_PCM_TRIGGER_RESUME:
 		if (cmd == SNDRV_PCM_TRIGGER_PAUSE_RELEASE)
@@ -928,7 +928,7 @@ static int snd_emu10k1_efx_playback_trigger(struct snd_pcm_substream *substream,
 		}
 		snd_emu10k1_playback_invalidate_cache(emu, 1, epcm->extra);
 
-		/* follow thru */
+		/* fall through */
 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
 	case SNDRV_PCM_TRIGGER_RESUME:
 		snd_emu10k1_playback_prepare_voice(emu, epcm->extra, 1, 1, NULL);