xf86Init: provide ddxBeforeReset ifdef DDXBEFORERESET

This is necessary when building Xorg and XWin simultaneously, otherwise
undefined symbol errors result in sdksyms.c.

Signed-off-by: Yaakov Selkowitz <yselkowitz@users.sourceforge.net>
Reviewed-by: Jon TURNEY <jon.turney@dronecode.org.uk>
Reviewed-by: Jeremy Huddleston <jeremyhu@apple.com>

hw/xfree86/common/xf86Init.c

@@ -1580,3 +1580,10 @@ xf86GetBppFromDepth(ScrnInfoPtr pScrn, int depth)
     else
         return 0;
 }
+
+#ifdef DDXBEFORERESET
+void
+ddxBeforeReset(void)
+{
+}
+#endif