ALSA: usb-audio: Update documentation comment for MS2109 quirk

commit 74a2a7de81a2ef20732ec02087314e92692a7a1b upstream.

As the recent fix addressed the channel swap problem more properly,
update the comment as well.

Fixes: 1b7ecc241a67 ("ALSA: usb-audio: work around streaming quirk for MacroSilicon MS2109")
Signed-off-by: Hector Martin <marcan@marcan.st>
Link: https://lore.kernel.org/r/20200816084431.102151-1-marcan@marcan.st
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/sound/usb/quirks-table.h b/sound/usb/quirks-table.h
index 89b7030..83f72dd 100644
--- a/sound/usb/quirks-table.h
+++ b/sound/usb/quirks-table.h
@@ -3524,8 +3524,8 @@
  * they pretend to be 96kHz mono as a workaround for stereo being broken
  * by that...
  *
- * They also have swapped L-R channels, but that's for userspace to deal
- * with.
+ * They also have an issue with initial stream alignment that causes the
+ * channels to be swapped and out of phase, which is dealt with in quirks.c.
  */
 {
 	.match_flags = USB_DEVICE_ID_MATCH_DEVICE |