ALSA: usb-audio: use a format bitmask per alternate setting

In preparation for USB audio 2.0 support, change the audioformat
structure so that it uses a bitmask to specify possible formats.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/usb/card.h b/sound/usb/card.h
index 856d71b..ed92420 100644
--- a/sound/usb/card.h
+++ b/sound/usb/card.h
@@ -9,7 +9,7 @@
 
 struct audioformat {
 	struct list_head list;
-	snd_pcm_format_t format;	/* format type */
+	u64 formats;			/* ALSA format bits */
 	unsigned int channels;		/* # channels */
 	unsigned int fmt_type;		/* USB audio format type (1-3) */
 	unsigned int frame_size;	/* samples per frame for non-audio */