ALSA: usb-audio: use usb headers rather than define structs locally

Use struct definitions from linux/usb/midi.h rather than locally
define the structs in sound/usb/midi.c.
Signed-off-by: George Harker <george@george-graphics.co.uk>
Link: https://lore.kernel.org/r/20210226212457.24538-1-george@george-graphics.co.ukSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/usb/midi.c

@@ -47,6 +47,7 @@
 #include <linux/usb.h>
 #include <linux/wait.h>
 #include <linux/usb/audio.h>
+#include <linux/usb/midi.h>
 #include <linux/module.h>
 
 #include <sound/core.h>
@@ -77,23 +78,6 @@ MODULE_AUTHOR("Clemens Ladisch <clemens@ladisch.de>");
 MODULE_DESCRIPTION("USB Audio/MIDI helper module");
 MODULE_LICENSE("Dual BSD/GPL");
 
-
-struct usb_ms_header_descriptor {
-	__u8  bLength;
-	__u8  bDescriptorType;
-	__u8  bDescriptorSubtype;
-	__u8  bcdMSC[2];
-	__le16 wTotalLength;
-} __attribute__ ((packed));
-
-struct usb_ms_endpoint_descriptor {
-	__u8  bLength;
-	__u8  bDescriptorType;
-	__u8  bDescriptorSubtype;
-	__u8  bNumEmbMIDIJack;
-	__u8  baAssocJackID[];
-} __attribute__ ((packed));
-
 struct snd_usb_midi_in_endpoint;
 struct snd_usb_midi_out_endpoint;
 struct snd_usb_midi_endpoint;
@@ -1875,7 +1859,7 @@ static int snd_usbmidi_get_ms_info(struct snd_usb_midi *umidi,
 	    ms_header->bDescriptorType == USB_DT_CS_INTERFACE &&
 	    ms_header->bDescriptorSubtype == UAC_HEADER)
 		dev_dbg(&umidi->dev->dev, "MIDIStreaming version %02x.%02x\n",
-			    ms_header->bcdMSC[1], ms_header->bcdMSC[0]);
+			    ((uint8_t *)&ms_header->bcdMSC)[1], ((uint8_t *)&ms_header->bcdMSC)[0]);
 	else
 		dev_warn(&umidi->dev->dev,
 			 "MIDIStreaming interface descriptor not found\n");