Revert "ALSA: usb-audio: Fix potential zero-division at parsing FU"

The commit 8428a8eb ("ALSA: usb-audio: Fix potential zero-division
at parsing FU") is utterly bogus and breaks the case with csize=1
instead of fixing anything.  Just take it back again.
Reported-by: NJörg Otte <jrg.otte@gmail.com>
Fixes: 8428a8eb ("ALSA: usb-audio: Fix potential zero-division at parsing FU"
Signed-off-by: NTakashi Iwai <tiwai@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

sound/usb/mixer.c

@@ -1476,9 +1476,9 @@ static int parse_audio_feature_unit(struct mixer_build *state, int unitid,
 			return -EINVAL;
 		}
 		csize = hdr->bControlSize;
-		if (csize <= 1) {
+		if (!csize) {
 			usb_audio_dbg(state->chip,
-				      "unit %u: invalid bControlSize <= 1\n",
+				      "unit %u: invalid bControlSize == 0\n",
 				      unitid);
 			return -EINVAL;
 		}