ALSA: line6: Fix POD HD500 audio playback

Apparently interface 1 is control interface akin to HD500X,
setting LINE6_CAP_CONTROL and choosing it as ctrl_if fixes
audio playback on POD HD500.

Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200425201115.3430-1-anarsoul@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/usb/line6/podhd.c

@@ -21,8 +21,7 @@
 enum {
 	LINE6_PODHD300,
 	LINE6_PODHD400,
-	LINE6_PODHD500_0,
-	LINE6_PODHD500_1,
+	LINE6_PODHD500,
 	LINE6_PODX3,
 	LINE6_PODX3LIVE,
 	LINE6_PODHD500X,
@@ -318,8 +317,7 @@ static const struct usb_device_id podhd_id_table[] = {
 	/* TODO: no need to alloc data interfaces when only audio is used */
 	{ LINE6_DEVICE(0x5057),    .driver_info = LINE6_PODHD300 },
 	{ LINE6_DEVICE(0x5058),    .driver_info = LINE6_PODHD400 },
-	{ LINE6_IF_NUM(0x414D, 0), .driver_info = LINE6_PODHD500_0 },
-	{ LINE6_IF_NUM(0x414D, 1), .driver_info = LINE6_PODHD500_1 },
+	{ LINE6_IF_NUM(0x414D, 0), .driver_info = LINE6_PODHD500 },
 	{ LINE6_IF_NUM(0x414A, 0), .driver_info = LINE6_PODX3 },
 	{ LINE6_IF_NUM(0x414B, 0), .driver_info = LINE6_PODX3LIVE },
 	{ LINE6_IF_NUM(0x4159, 0), .driver_info = LINE6_PODHD500X },
@@ -352,23 +350,13 @@ static const struct line6_properties podhd_properties_table[] = {
 		.ep_audio_r = 0x82,
 		.ep_audio_w = 0x01,
 	},
-	[LINE6_PODHD500_0] = {
+	[LINE6_PODHD500] = {
 		.id = "PODHD500",
 		.name = "POD HD500",
-		.capabilities	= LINE6_CAP_PCM
+		.capabilities	= LINE6_CAP_PCM | LINE6_CAP_CONTROL
 				| LINE6_CAP_HWMON,
 		.altsetting = 1,
-		.ep_ctrl_r = 0x81,
-		.ep_ctrl_w = 0x01,
-		.ep_audio_r = 0x86,
-		.ep_audio_w = 0x02,
-	},
-	[LINE6_PODHD500_1] = {
-		.id = "PODHD500",
-		.name = "POD HD500",
-		.capabilities	= LINE6_CAP_PCM
-				| LINE6_CAP_HWMON,
-		.altsetting = 0,
+		.ctrl_if = 1,
 		.ep_ctrl_r = 0x81,
 		.ep_ctrl_w = 0x01,
 		.ep_audio_r = 0x86,