ALSA: vx_core: remove warning for empty loop body

Fix W=1 warning.

sound/drivers/vx/vx_core.c: In function ‘snd_vx_threaded_irq_handler’:
sound/drivers/vx/vx_core.c:515:3: warning: suggest braces around empty
body in an ‘if’ statement [-Wempty-body]
  515 |   ; /* so far, nothing to do yet */
      |   ^

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20200702193604.169059-23-pierre-louis.bossart@linux.intel.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/drivers/vx/vx_core.c

@@ -511,8 +511,9 @@ irqreturn_t snd_vx_threaded_irq_handler(int irq, void *dev)
 	/* The start on time code conditions are filled (ie the time code
 	 * received by the board is equal to one of those given to it).
 	 */
-	if (events & TIME_CODE_EVENT_PENDING)
+	if (events & TIME_CODE_EVENT_PENDING) {
 		; /* so far, nothing to do yet */
+	}
 
 	/* The frequency has changed on the board (UER mode). */
 	if (events & FREQUENCY_CHANGE_EVENT_PENDING)