ALSA: usb-audio: add quirk flag to enable native DSD for McIntosh devices

McIntosh devices supporting native DSD require the feature to be
explicitly exposed. Add a flag that fixes an issue where DSD audio was
defaulting to DSD over PCM instead of delivering raw DSD data.
Signed-off-by: Max McCarthy <mmccarthy@mcintoshlabs.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/BL0PR13MB4433226005162D186A8DFF4AD6DFA@BL0PR13MB4433.namprd13.prod.outlook.comSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/usb/quirks.c

@@ -2220,6 +2220,8 @@ static const struct usb_audio_quirk_flags_table quirk_flags_table[] = {
 		   QUIRK_FLAG_DSD_RAW),
 	VENDOR_FLG(0x2ab6, /* T+A devices */
 		   QUIRK_FLAG_DSD_RAW),
+	VENDOR_FLG(0x2afd, /* McIntosh Laboratory, Inc. */
+		   QUIRK_FLAG_DSD_RAW),
 	VENDOR_FLG(0x2d87, /* Cayin device */
 		   QUIRK_FLAG_DSD_RAW),
 	VENDOR_FLG(0x3336, /* HEM devices */