ALSA: seq: oss: Use the standard fall-through annotation

As a preparatory patch for the upcoming -Wimplicit-fallthrough
compiler checks, replace with the standard "fall through" annotation.
Unfortunately gcc doesn't understand a chattier text.
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

sound/core/seq/oss/seq_oss_timer.c

@@ -92,7 +92,7 @@ snd_seq_oss_process_timer_event(struct seq_oss_timer *rec, union evrec *ev)
 		case TMR_WAIT_REL:
 			parm += rec->cur_tick;
 			rec->realtime = 0;
-			/* fall through and continue to next */
+			/* fall through */
 		case TMR_WAIT_ABS:
 			if (parm == 0) {
 				rec->realtime = 1;