atusb/fw2/: assigned hardware revision code point; some cleanup

- fw/include/atusb/ep0.h (HW_TYPE_110131): defined hardware type 2 for
  ATmega32U2-based boards
- fw/ep0.c: define HW_TYPE as HW_TYPE_110131, not directly as 2
- fw2/atusb.c: include atusb/ep0.h instead of declaring ep0_init locally

atusb/fw/include/atusb/ep0.h

@@ -1,8 +1,8 @@
 /*
  * include/atusb/ep0.h - EP0 extension protocol
  *
- * Written 2008-2010 by Werner Almesberger
- * Copyright 2008-2010 Werner Almesberger
+ * Written 2008-2011 by Werner Almesberger
+ * Copyright 2008-2011 Werner Almesberger
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -45,6 +45,7 @@
 
 #define	HW_TYPE_100813	0	/* 2010-08-13 */
 #define	HW_TYPE_101216	1	/* 2010-12-16 */
+#define	HW_TYPE_110131	2	/* 2011-01-31, ATmega32U2-based */
 
 
 /*

atusb/fw2/atusb.c

@@ -10,9 +10,7 @@
 #include "at86rf230.h"
 #include "board.h"
 #include "spi.h"
-
-
-void ep0_init(void);
+#include "atusb/ep0.h"
 
 
 int main(void)

atusb/fw2/ep0.c

@@ -31,7 +31,7 @@
 #include "spi.h"
 
 
-#define	HW_TYPE		2	/* @@@ needs more work */
+#define	HW_TYPE		HW_TYPE_110131
 static const char *build_date = "today";
 static unsigned build_number = 42;