ALSA: Use fallthrough pseudo-keyword

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20200708203236.GA5112@embeddedor
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/atmel/ac97c.c b/sound/atmel/ac97c.c
index a1dce97..a62f1cd 100644
--- a/sound/atmel/ac97c.c
+++ b/sound/atmel/ac97c.c
@@ -356,14 +356,14 @@ atmel_ac97c_playback_trigger(struct snd_pcm_substream *substream, int cmd)
 	camr = ac97c_readl(chip, CAMR);
 
 	switch (cmd) {
-	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE: /* fall through */
-	case SNDRV_PCM_TRIGGER_RESUME: /* fall through */
+	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+	case SNDRV_PCM_TRIGGER_RESUME:
 	case SNDRV_PCM_TRIGGER_START:
 		ptcr = ATMEL_PDC_TXTEN;
 		camr |= AC97C_CMR_CENA | AC97C_CSR_ENDTX;
 		break;
-	case SNDRV_PCM_TRIGGER_PAUSE_PUSH: /* fall through */
-	case SNDRV_PCM_TRIGGER_SUSPEND: /* fall through */
+	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+	case SNDRV_PCM_TRIGGER_SUSPEND:
 	case SNDRV_PCM_TRIGGER_STOP:
 		ptcr |= ATMEL_PDC_TXTDIS;
 		if (chip->opened <= 1)
@@ -388,14 +388,14 @@ atmel_ac97c_capture_trigger(struct snd_pcm_substream *substream, int cmd)
 	ptcr = readl(chip->regs + ATMEL_PDC_PTSR);
 
 	switch (cmd) {
-	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE: /* fall through */
-	case SNDRV_PCM_TRIGGER_RESUME: /* fall through */
+	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+	case SNDRV_PCM_TRIGGER_RESUME:
 	case SNDRV_PCM_TRIGGER_START:
 		ptcr = ATMEL_PDC_RXTEN;
 		camr |= AC97C_CMR_CENA | AC97C_CSR_ENDRX;
 		break;
-	case SNDRV_PCM_TRIGGER_PAUSE_PUSH: /* fall through */
-	case SNDRV_PCM_TRIGGER_SUSPEND: /* fall through */
+	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+	case SNDRV_PCM_TRIGGER_SUSPEND:
 	case SNDRV_PCM_TRIGGER_STOP:
 		ptcr |= ATMEL_PDC_RXTDIS;
 		if (chip->opened <= 1)