sandbox: sound: Handle errors better in sound_beep()

At present an error does not stop the sound-output loop. This is incorrect
since nothing can be gained by trying to continue. Fix it.
Signed-off-by: NSimon Glass <sjg@chromium.org>

drivers/sound/sound-uclass.c

@@ -97,11 +97,14 @@ int sound_beep(struct udevice *dev, int msecs, int frequency_hz)
 	sound_create_square_wave(i2s_uc_priv->samplingrate, data, data_size,
 				 frequency_hz, i2s_uc_priv->channels);
 
+	ret = 0;
 	while (msecs >= 1000) {
 		ret = sound_play(dev, data, data_size);
+		if (ret)
+			break;
 		msecs -= 1000;
 	}
-	if (msecs) {
+	if (!ret && msecs) {
 		unsigned long size =
 			(data_size * msecs) / (sizeof(int) * 1000);