ALSA: line6: Remove driver version from header comment

The driver version string was removed in an ealier commit for being
useless.  These are equally useless.

Signed-off-by: Chris Rorvick <chris@rorvick.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/usb/line6/midibuf.h

@@ -1,5 +1,5 @@
 /*
- * Line 6 Linux USB driver - 0.9.1beta
+ * Line 6 Linux USB driver
  *
  * Copyright (C) 2004-2010 Markus Grabner (grabner@icg.tugraz.at)
  *