include/linux/usb/audio.h: add __attribute__((packed))

This was missing on the definition of struct uac_iso_endpoint_descriptor

Signed-off-by: Daniel Mack <daniel@caiaq.de>
Cc: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/include/linux/usb/audio.h b/include/linux/usb/audio.h
index 57f20551..9fae6bd 100644
--- a/include/linux/usb/audio.h
+++ b/include/linux/usb/audio.h
@@ -456,7 +456,7 @@
 	__u8  bmAttributes;
 	__u8  bLockDelayUnits;
 	__le16 wLockDelay;
-};
+} __attribute__((packed));
 #define UAC_ISO_ENDPOINT_DESC_SIZE	7
 
 #define UAC_EP_CS_ATTR_SAMPLE_RATE	0x01