staging/xgifb: Include sis initdef.h header

This patch includes the initdef.h header from the sis driver.
Since the xgi driver used to redefine a lot of stuff from the sis
driver, we can simply include the headers of the sis driver itself, so
we can remove duplicated stuff later on.

In order to include the initdef.h we have to rename the header guards.
Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/xgifb/vb_def.h

 /* $XFree86: xc/programs/Xserver/hw/xfree86/drivers/xgi/initdef.h
  * ,v 1.4 2000/12/02 01:16:17 dawes Exp $*/
-#ifndef _INITDEF_
-#define _INITDEF_
+#ifndef _VB_DEF_
+#define _VB_DEF_
+#include "../../video/sis/initdef.h"
 
 #define VB_XGI301C      0x0020 /* for 301C */
 /*end 301b*/