staging: line6: rename MidiBuffer to avoid CamelCase

Fix checkpatch.pl warnings related to MidiBuffer:

  WARNING: Avoid CamelCase: <MidiBuffer>
  #947: FILE: staging/line6/driver.c:363:
  +       struct MidiBuffer *mb = &line6->line6midi->midibuf_in;

Rename MidiBuffer to midi_buffer.

Note that "midibuf" would be another good name but sound/oss/midibuf.c
already uses it for a different concept.  Avoid possible confusion by
using "midi_buffer" instead.

Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/staging/line6/midi.h b/drivers/staging/line6/midi.h
index 19dabd5..78f903f 100644
--- a/drivers/staging/line6/midi.h
+++ b/drivers/staging/line6/midi.h
@@ -57,12 +57,12 @@
 	/**
 		 Buffer for incoming MIDI stream.
 	*/
-	struct MidiBuffer midibuf_in;
+	struct midi_buffer midibuf_in;
 
 	/**
 		 Buffer for outgoing MIDI stream.
 	*/
-	struct MidiBuffer midibuf_out;
+	struct midi_buffer midibuf_out;
 };
 
 extern int line6_init_midi(struct usb_line6 *line6);