Make libva pass compilation with old DRI2 proto which dri2tokens.h hasn't DRI2DriverDRI definition

Signed-off-by: root <root@Austin-Develop.localdomain>

src/X11/va_dri2.c

@@ -37,8 +37,13 @@
 #include <X11/extensions/extutil.h>
 #include "xf86drm.h"
 #include "va_dri2.h"
+#include "va_dri2tokens.h"
 #include "va_dri2str.h"
 
+#ifndef DRI2DriverDRI
+#define DRI2DriverDRI 0
+#endif
+
 static char va_dri2ExtensionName[] = DRI2_NAME;
 static XExtensionInfo _va_dri2_info_data;
 static XExtensionInfo *va_dri2Info = &_va_dri2_info_data;