ALSA: xen: Remove superfluous fall through comments

The "fall through" comments found in switch-cases in ALSA xen driver
are all superfluous.  The kernel coding style allows the multiple
cases in a row.  Let's remove them.
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20200709111750.8337-3-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/xen/xen_snd_front.c

@@ -246,11 +246,8 @@ static void sndback_changed(struct xenbus_device *xb_dev,
 
 	switch (backend_state) {
 	case XenbusStateReconfiguring:
-		/* fall through */
 	case XenbusStateReconfigured:
-		/* fall through */
 	case XenbusStateInitialised:
-		/* fall through */
 		break;
 
 	case XenbusStateInitialising:
@@ -289,7 +286,6 @@ static void sndback_changed(struct xenbus_device *xb_dev,
 		break;
 
 	case XenbusStateUnknown:
-		/* fall through */
 	case XenbusStateClosed:
 		if (xb_dev->state == XenbusStateClosed)
 			break;

sound/xen/xen_snd_front_evtchnl.c

@@ -46,13 +46,9 @@ static irqreturn_t evtchnl_interrupt_req(int irq, void *dev_id)
 			continue;
 		switch (resp->operation) {
 		case XENSND_OP_OPEN:
-			/* fall through */
 		case XENSND_OP_CLOSE:
-			/* fall through */
 		case XENSND_OP_READ:
-			/* fall through */
 		case XENSND_OP_WRITE:
-			/* fall through */
 		case XENSND_OP_TRIGGER:
 			channel->u.req.resp_status = resp->status;
 			complete(&channel->u.req.completion);