ALSA: line6: Split to each driver

Split to each individual driver for POD, PODHD, TonePort and Variax
with a core LINE6 helper module.  The new modules follow the standard
ALSA naming rule with snd prefix: snd-usb-pod, snd-usb-podhd,
snd-usb-toneport and snd-usb-variax, together with the corresponding
CONFIG_SND_USB_* Kconfig items.

Tested-by: Chris Rorvick <chris@rorvick.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/usb/line6/midi.c b/sound/usb/line6/midi.c
index c9d725a..2a42d53 100644
--- a/sound/usb/line6/midi.c
+++ b/sound/usb/line6/midi.c
@@ -11,13 +11,13 @@
 
 #include <linux/slab.h>
 #include <linux/usb.h>
+#include <linux/export.h>
 #include <sound/core.h>
 #include <sound/rawmidi.h>
 
 #include "audio.h"
 #include "driver.h"
 #include "midi.h"
-#include "pod.h"
 #include "usbdefs.h"
 
 #define line6_rawmidi_substream_midi(substream) \
@@ -319,3 +319,4 @@
 	spin_lock_init(&line6midi->midi_transmit_lock);
 	return 0;
 }
+EXPORT_SYMBOL_GPL(line6_init_midi);