ALSA: usb: Avoid VLA in mixer_us16x08.c

This is another attempt to work around the VLA used in
mixer_us16x08.c.  Basically the temporary array is used individually
for two cases, and we can declare locally in each block, instead of
hackish max() usage.
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/usb/mixer_us16x08.c

@@ -698,16 +698,18 @@ static int snd_us16x08_meter_get(struct snd_kcontrol *kcontrol,
 	struct snd_usb_audio *chip = elem->head.mixer->chip;
 	struct snd_us16x08_meter_store *store = elem->private_data;
 	u8 meter_urb[64];
-	char tmp[max(sizeof(mix_init_msg1), sizeof(mix_init_msg2))];
 
 	switch (kcontrol->private_value) {
-	case 0:
+	case 0: {
+		char tmp[sizeof(mix_init_msg1)];
+
 		memcpy(tmp, mix_init_msg1, sizeof(mix_init_msg1));
 		snd_us16x08_send_urb(chip, tmp, 4);
 		snd_us16x08_recv_urb(chip, meter_urb,
 			sizeof(meter_urb));
 		kcontrol->private_value++;
 		break;
+	}
 	case 1:
 		snd_us16x08_recv_urb(chip, meter_urb,
 			sizeof(meter_urb));
@@ -718,7 +720,9 @@ static int snd_us16x08_meter_get(struct snd_kcontrol *kcontrol,
 			sizeof(meter_urb));
 		kcontrol->private_value++;
 		break;
-	case 3:
+	case 3: {
+		char tmp[sizeof(mix_init_msg2)];
+
 		memcpy(tmp, mix_init_msg2, sizeof(mix_init_msg2));
 		tmp[2] = snd_get_meter_comp_index(store);
 		snd_us16x08_send_urb(chip, tmp, 10);
@@ -727,6 +731,7 @@ static int snd_us16x08_meter_get(struct snd_kcontrol *kcontrol,
 		kcontrol->private_value = 0;
 		break;
 	}
+	}
 
 	for (set = 0; set < 6; set++)
 		get_meter_levels_from_urb(set, store, meter_urb);